The Ultimate Guide to Homebrew Spells in D&D 5e

What’s up designers, and welcome back to Rempton Games. In today’s video I want to take a look at homebrewing spells in D&D – how it’s done and what factors need to be taken into account, and share some simple example spells that I prepared earlier. I’ve broken this video into a few sections – first, we’ll talk about some basic information that applies to all homebrew spells. Next, we’ll talk about specific categories of spells, including damage spells, healing spells, summoning spells, and buff / debuff spells. Finally, we’ll finish with a look at some edge-cases, including bonus action and reaction spells, rituals, and cantrips. Without further ado, let’s get started! 

Basic Spell Info

Before we start homebrewing specific types of spells, let’s go over some basic information that applies to ALL types of spells that we might try to create. The first step to designing any spell is to come up with a concept for what the spell should do. This concept could be something cool you read about in a book or saw in an anime, or it could be an interesting mechanical idea. 

Once you have a concept, the next step is to make sure that what you want to make doesn’t already exist. D&D 5e has hundreds of spells, so there is probably a spell out there already for most things that you might want to do. I like to use Dndbeyond’s spell search tool for this – you can use various keywords and filters to try to locate the spell you are looking for. 

The third step is reflavoring – even if there isn’t a spell out there that does ~exactly~ what you want, there might be something close enough that you can easily reflavor it. For example, suppose you want something similar to Gambit from the X-Men’s ability to throw exploding cards at his enemies. A number of spells could be reflavored to fit this concept – Eldritch Blast, Magic Missile, or scorching ray could all work.

If you search and simply can’t find something that fits what you are looking for, then it’s time to homebrew! That’s what this video is about, and in the remaining sections I’ll be discussing and homebrewing all kinds of different spells. However, keep in mind that homebrewing isn’t the final step. The final step is a cycle of playtesting and tweaking your spells. While the guidelines in this video will help you get in the right ballpark, the only way to know whether your spell is actually fun and balanced is to use it, see what happens, and make adjustments if needed. With all of that out of the way, let’s start designing some spells!

Damage Spells

Let’s start by looking at what is probably the most straightforward aspect of designing a spell. – dealing damage. The DMG has a table that gives a rough guideline on how much damage spells of different levels should do – from 1d10 for a cantrip, all the way up to 15d10 for a 9th level spell. This table also has two columns – one for single-target spells, and another for multi-target spells, with multiple targets understandably dealing less damage. However, this table is really just scratching the surface. Even if your spell is ONLY dealing damage, there are a number of other factors that affect how much damage it can deal. These include the type of damage, whether it deals half-damage on a save, how long it lasts, and the details of the area-of-effect.

Not all damage types are made equal in D&D. Certain types of damage are widely resisted – basically all fiends and many dragons are resistant or immune to fire damage, tons of undead are resistant or immune to necrotic damage, and basically everything is immune to poison. If your spell deals one of these damage types, you might be able to get away with slightly higher damage, since it’s so commonly resisted. Fire spells, in particular, tend to deal a bit more damage than spells of other types – burning hands, for example, deals 3d6 damage, instead of the 2d6 recommended for a 1st level AOE spell.

On the flip side, force damage is basically never resisted, and radiant and psychic resistances are also very rare, so spells that use these damage types might need to be either a bit less powerful, or potentially require a higher level spell slot. For example, Synaptic Static does the same amount of damage as a Fireball, but is a 5th level spell instead of 3rd, with the main difference being that it has a better damage type (psychic instead of fire), with a better saving throw (intelligence instead of dexterity). True, it has the additional effect of muddling the minds of those that it hits, but it would definitely still be at least a 4th level spell even without that. 

Most spells require a saving throw before they do damage, and tend to do half-damage if the target succeeds on the save. If the target takes no damage on a successful save, then the spell can deal additional damage – the DMG recommends about 25% more. A good example of this is the spell Disintegrate, which does 10d6 + 40 damage on a failed save, and none on a success. This averages out to 75 damage, which is around 30% percent more than the recommended 55 (10d10) damage for a single-target 6th level spell.

It’s also important to keep in mind how long the spell lasts when calculating its average damage. Take the spell Spirit Guardians, which does damage to all creatures within 15 feet of you. Spirit Guardians is a great spell, but it only does an average of 13.5 (3d8) damage, which is lower than the 21 (6d6) recommended by the DMG. This is because Spirit Guardians sticks around for multiple turns – it lasts up to 10 minutes, although no combat is going to last that long. Most combats last 3-4 turns, and Spirit Guardians doesn’t actually deal damage until a creature begins its turn in the area, so it’ll usually be dealing damage for 2-3 rounds. This means that it can actually exceed the damage done by Fireball, especially in a longer combat. If a spell can continue dealing damage for an entire combat encounter, the damage should typically be about ½ to ⅔ as much as a single use spell.

There are also certain spells that allow you to attack repeatedly on subsequent turns as either an action or bonus action. If using an action, these spells tend to do about ½ as much damage as a single-use spell of the same level. For example, Sunbeam does 6d6 damage, which is roughly half of the 11d6 recommended for a 6th level spell that can hit multiple targets. Bigby’s Hand, on the other foot, can deal 4d8 force damage as a bonus action. This averages to 18 damage, which is about ⅓ of 55 damage recommended for a single target 5th level spell that does not damage on a save.

When designing an AOE spell, the size and shape of the area of effect also determine how powerful the spell is. When discussing AOE spells it’s important to distinguish between the range of the spell, and the size of the AOE. The range determines how far away you can cast the spell – the spell can originate from anywhere within the range. The size of the AOE determines how much area is affected by the spell. Evard’s Black Tentacles, for example, has a range of 90 feet, but can only effect a 20 foot square. In broad strokes, long ranges tend to be better than short ones and bigger AOEs tend to be better than small ones, although there are diminishing returns to both. A range of 30 feet is definitely better than a range of touch, because you can attack without putting yourself in danger, but the difference between a range of 120 feet and 300 feet is negligible. In addition, not all AOE shapes are made equal – cones and lines give you better control over who you target than spheres or cubes, and make it less likely to accidentally damage your allies. Individually most of these factors are relatively small, but together they may require you to adjust your spells damage up or down slightly.

The final factor is whether your spell requires an attack roll or a saving throw. In most cases this won’t actually make a big difference in the power level of your spell,  as it really depends on the monster whether they have better AC or saving throws, and what defense your spell targets is really a matter of flavor. However, keep in mind that spells that require attack rolls should be treated similarly to spells that deal 0 damage on a save, so they should get the same 25% boost. Also keep in mind that not all saves are made equal – while different monsters have different strengths, the best stat to target tends to be intelligence, as it is the weakest stat for most monsters. This is followed by dexterity, wisdom, strength, and constitution. Charisma is a bit of an outlier – most low level monsters tend to have pretty bad charisma, but at higher levels it actually tends to be one of their strongest stats. 

That’s a lot of information, so let’s put it into action and make some spells! Because there are so many different types of damage spells, I prepared two – one with a single target, and one AOE. For the single target spell I went pretty simple – its a spell called Icicle spear, which you can see on screen, and it allows you to launch an icicle at an enemy within range. It’s a 3rd level single target spell, which gives us a damage budget of 5d10 or about 27 damage, but because it does 0 damage on a miss we actually boost it up about 25% to get 34 damage. If we roll 10d6 that would give us a total of 35 damage, which is very close. From there I decided to split the damage to be ½ piercing and ½ cold, and there’s our spell!

The second spell is a 5th level AOE spell called Acid Pool. It creates a pool of corrosive green acide that lasts for 10 minutes. The damage budget for a 5th level AOE spell is 8d6 or 28 damage, but because this spell sticks around for multiple rounds we want our damage to be between ½ to ⅔ that amount, which means somewhere between 14 to 21 damage. I chose to deal 4d8, which is about 18 damage – well within the desired range.

Healing Spells

Spells can deal damage, but they can also take it away. According to the DMG you can use the same tables that determine damage to determine how much healing a spell should do, but this isn’t really the case. The first caveat is that cantrips should never provide healing – even if they only provide 1 hit point, the spell can always be used outside of combat to heal the party up to full outside of combat. The second is that, in practice, low level healing spells actually tend to heal significantly less than a damage spell could deal. Cure Wounds heals around 8 damage on average, whereas the equivalent damaging spell – inflict wounds – deals around 16. Aura of Vitality is a 3rd level AOE spell centered on you that lets you heal 7 (2d6) damage to one creature in range each turn. Compare that to Spirit Guardians, which can deal 16 damage to multiple creatures each turn. This pattern continues through level 5 – healing spells tend to only do around half as much healing as an equivalent damage spell, and often have additional restrictions to boot. However, the pattern flips at level 6, and at high levels healing spells can actually heal MORE than an equivalent damage spell. The 6th level spell Heal can heal 70 hit points – more than the 55 recommended damage for a spell of that level – and the 9th level spell Mass Heal can heal up to 700 total Hit points!

In addition to restoring hit-points, healing spells can also bring creatures back to life, cure curses and conditions, or grant temporary hit points. If including these effects as part of your healing, be sure to reference what other healing spells are capable of at similar levels.

There are already a lot of healing spells out there, so it was a bit difficult to find a niche that hasn’t already been filled. However, I noticed that there are very few healing spells that also do damage, and also no healing spells at 8th level, so let’s make an 8th level “Life Drain” spell!

Because it’s level 8, we want the spell to be pretty powerful and impressive, so I’m going to build it off of the chassis of one of my favorite spells in the game – spirit guardians. This spell creates a 15 foot aura around yourself that damages creatures when they enter the area or start their turn there, and also allows you to exclude any number of creatures from the effect. If cast as an 8th level spell, Spirit Guardians can do 8d8 radiant or necrotic damage, so we should use this as our base. We need to reduce this damage because we are also going to be healing – we could cut it in half, but because healing is cheaper than damage at higher levels let’s reduce the damage to 5d8, and we are basically done. You can see the finished spell on screen, or at the links in the description.

Summoning Spells

Summoning spells have changed a lot in D&D 5e. If you just want to design a modern style summoning spell you can skip to the next chapter, but stick around if you want to hear a rant on why the old summoning spells are such a pain to play with.

The original summoning spells, such as Conjure Animals or Conjure Elementals – had a lot of issues. First, most of them allowed you to summon existing creatures from the Monster Manual and other sources, and some of those creatures have special abilities that can be used in unexpected ways. A classic example of this is using Conjure Woodland Beings to summon 8 Pixies that can turn invisible and cast Polymorph and fly on the party, potentially creating a group of 4 flying T-rexes for the cost of a single fourth level spell. That particular combo was  busted from the beginning, but even if a particular summoning spell doesn’t do anything crazy NOW, it might in the future – as new creatures get added to the game these spells get additional targets, which means there is always the possibility of a new creature being added that totally breaks the spell. 

One way to mitigate this problem is to have the DM pick the creatures rather than the player who casts the spell. This is technically how the spells are supposed to work, with the player only deciding how many creatures to summon, but I know a lot of tables DO let the player choose which creatures they want.

On the other side you have something like Conjure Celestial, a 7th level spell that let you summon a Celestial of CR 4 or 5. The problem with this spell is that there are basically no targets – there are only 8 celestial creatures with a CR of 5 or less, and most of those are from expansions. If you only have the Monster Manual there are only 3 creatures you can even summon with this spell.

Another problem with these older style summoning spells was the sheer amount of time required to use them. Because you have to choose existing creatures it can take some time to choose what you want to summon, especially if you are summoning multiple creatures. Summoning lots of creatures can also lead to a very cluttered battlefield, and slow down combat with lots of extra actions.

Finally, these spells were extremely inconsistent – there was no rhyme or reason in terms of what CR could be summoned, how long the spell takes to cast, how long they last, etc.

Tasha’s Cauldron of Everything fixed all of this by coming out with a bunch of new summoning spells with a much more consistent format. These spells only allows players to summon a single creature, and this creature can be customized in a few different ways. The first is by choosing what type of creature to summon – usually from among three options provided by the spell, which affects some of the creature’s features. For example, the second level spell “Summon Beast” allows you to decide whether the creature lives in the air, on land, or in the water, and adjusts aspects accordingly. The second way to customize the creature is by changing the level of spell slot used to cast the spell – higher level slots make a more powerful creature, typically by increasing hit points, number of attacks, etc.

Designing these summoning spells is pretty tricky, because you have to design a creature stat block that can support multiple different options that all feel unique, but are also balanced. However, there are a number of “rules of thumb” that can make the process easier. First, the casting time should be 1 action, the duration should be 1 hour, and it should require concentration.The HP should have a base amount (which might vary between the different options), and it should scale based on the level of the spell (typically adding extra 5 or 10 extra HP for each spell level above the minimum). The number of attacks is usually equal to ½ the level of the spell (rounded down), and the damage dealt scales with the spell level. The creature’s base damage (if the spell is cast at its lowest level) is usually about ⅔ the amount of damage that could be dealt by a single target spell of the same level – which is really good, considering that the creature can attack multiple turns in a row. However, the creature’s offensive abilities usually outshine their defenses. 

With all of that out of the way, let’s try our hand at designing one of these bad boys! First, we need to decide what type of creature we will be summoning. The more recent summoning spells cover a lot of bases, but there are still a few categories of creatures that don’t have a summoning spell. For this example, I want to summon some plants.

All of the recent summoning spells allow you to customize the creature you summon by choosing one of three different options, so we need to choose some categories of plants for our players to summon. For this example, I chose trees, vines, and mushrooms. Yes, I know mushrooms are fungi and not plants, but 5e often lumps mushroom creatures with the plants, so we’ll go with it. 

Typically each creature gets a special feature or two based on its type. I decided to give the vine creature the “Entangling Vines” feature, which makes the area around it difficult terrain and allows it to restrain creatures. I gave the mushroom creature a rechargeable “Spores” ability, which lets it poison creatures around it and deal poison damage. For trees, I made them a bit beefier, with more AC and HP than the other two creatures. I also gave them all the “false appearance” trait, which makes them seem like normal plants when not moving. You can see the completed spell on screen, or in the links down below.

Buff and Debuff Spells, and Combining Effects

The next category of spells we will be discussing are buff and debuff spells, which are spells that make your characters stronger or your enemies weaker, respectively. The types of spells we have been talking about so far have been pretty straightforward because they basically did one thing, but buff and debuff spells are tricky because they can do such a huge variety of effects that straddle the line between combat bonuses and utility. These include changing a creature’s armor class, giving characters benefits on rolls, increasing damage, changing a creature’s shape, causing status conditions, creating difficult terrain, and so much more. 

The good news is that D&D already has spells that cover most of your bases when it comes to buffing and debuffing, and it’s unlikely that you will come across a new buff spell that isn’t at least similar to something that exists, which you can use as a reference for power level. For example, let’s say you wanted to make a buff spell that turns every hit that creature makes into a critical hit. A critical hit isn’t too different from simply attacking twice, so you could look at something like Haste as a reference.

The bad news is that most buff and debuff spells tend to combine these basic effects to make something more complicated and powerful. Take for instance the “Investiture” spells. There are four of them – one for fire, ice, stone, and wind, and each one combines 3 or 4 different abilities to buff your character in a way that fits each element. In order to create these types of spells, we need a technique for combining multiple effects into a single spell.

First, let’s choose two effects that we want to combine, such as flight and invisibility. To combine these effects we should first find reference spells for each part, which is actually pretty easy in this case. Flight can be granted by the “Fly” spell, which is a 3rd level spell, while true invisibility is granted by the “Greater Invisibility” spell – a fourth level spell. 

The next step is to convert the component spells into an equivalent amount of damage. A single target 3rd level spell is worth 5d10 damage, while fourth level spells are worth 6d10 damage. The next step is to combine these damage values to see how powerful the combined effect is. If we simply combined the values directly we would get 11d10, which would make the combination a 7th level spell. However, non-damage effects don’t tend to mix as well as simply adding does, and therefore the combined effect is rarely equal to the sum of its parts.

With effects like flight and invisibility it actually works pretty well, because these effects are very complimentary – an invisible flying character is a pretty big threat on the battlefield, and is much more powerful than either effect on its own. However, not all effects combine together so cleanly. If you have a spell that lets you read minds, you will cast that spell at a time that is optimal for reading minds. If you have a spell that gives you resistance to damage, you will cast that spell at a time that is optimal for resisting damage. However, if you have a spell that grants you resistance to damage AND lets you read minds, well…while it’s certainly more powerful than either component part individually, you are unlikely to be in a situation that is optimal for BOTH parts at the same time, so the package should come at a bit of a discount – around 20% is a good rule of thumb.

I called the final spell “Spectral Transformation”, and because we have a little wiggle room in our power budget I added the “Incorporeal Movement” feature, which is very common among 5e’s ghostly type monsters and lets you move through objects and creatures as if they were difficult terrain.

Bonus Action and Reaction Spells

Most of the spells we have been talking about so far in this video have required an action to cast, many spells can also be cast as a bonus action or a reaction, and these types of spells have a few extra considerations. Bonus action spells are typically designed to enhance your main action or your movement in some way. For example, the cantrip Shillelagh is a bonus action because it enhances your attack action, and Expeditious Retreat allows you to dash as a bonus action – effectively doubling your movement.

Reaction spells, on the other hand, are reactive! There aren’t that many reaction spells, but they tend to be some of the best defensive spells in the game – things like Shield which can raise your AC in response to an attack, or Counterspell, which lets you stop an enemy from casting a spell. Typically you should only make a spell require a reaction if that’s baked into the concept of the spell – it should be something that requires specific timing, and wouldn’t make sense as something that’s just an action on your turn. 

Surprisingly, there isn’t a reaction teleportation spell that lets you get out of danger, so lets make one! The idea is simple – it triggers when you are targeted by an attack, or are in the area of affect of a spell, and lets you teleport away. It would be similar to Misty Step, which is a second level spell, but because of the reactive nature of it I actually think it should be higher than 2nd level. It’s also probably weaker than Temporal Shunt, which lets you cancel any attack or spell by moving the enemy through time, so I think it would make sense as either a 3rd or fourth level spell. The question is whether this steps on Counterspell’s toes too much – however, I don’t think so, because it only affects you, although maybe it can effect multiple creatures if cast using a higher level slot. You can see the finished spell – Emergency Escape – on the screen, or at the links in the description.

Ritual Spells

Ritual Spells are unique because they can be cast without using a spell slot, but in order to do so they take an extra 10 minutes to cast. Because of this, these are definitely NOT combat spells – rituals are designed to be used when you are far away from danger, and time is not a huge factor. These spells are often used to gather information – such as Detect Magic, convey information, like Alarm or Skywrite, or provide out of combat utility, such as Wristpocket or Leomund’s Tiny Hut. An important thing to keep in mind with ritual spells is that, because they don’t require a spell slot, there is no limit to the number of times they can be cast (other than casting time). Because of this, you should make sure that the effect isn’t something that would be overpowered or game breaking if cast repeatedly (which is probably the reason that there isn’t a healing ritual).

This ritual spell is probably my favorite one from this video – I call it “Professor Mercury’s Automatic Stagecoach”, and it lets you summon a self-driving stagecoach. This combines aspects of several different ritual spells – it can be used to carry objects like Tenser’s Floating Disk, but it can also be used to move characters – similarly to the Phantom Steed spell, and provides some protection to the party, like a Tiny Hut. Using the technique for combining spell effects that we discussed earlier in the video, I decided to make this spell a 5th level spell, and gave it a costly material component to counteract the cost of simply buying carriages and horses. I can’t wait to give this spell a try in future games!

Cantrips

The final category of spells that we need to talk about today are cantrips – specifically utility cantrips. Utility cantrips are small effects players can activate without using a spell slot, and should provide an effect that is equally useful at level 1 as it is at level 20. Some good examples are Mage Hand, which can move small objects at a distance, or Minor Illusion which can create…minor illusions. These types of effects are very tricky to design – much like Ritual Spells they need to be the type of thing that can be cast infinitely, but unlike Rituals they don’t have the balancing factors of a higher casting time or higher spell levels. However, I think I’ve come up with something. 

I call it “Shade”, and it’s basically the counterpart to the “Light” cantrip. You touch an object and imbue it with darkness. Within a 30 foot radius of the object non-magical bright light is treated as dim light, and non-magical dim light is treated as darkness. That’s it! It’s a pretty small effect, but I think it could be pretty useful with some creativity.

Conclusion

That’s all I have for this week! I hope this video was helpful, and if it helped you with your homebrew spells I would love to hear about them. I would also love to hear if you use any of the spells from this video in your home games, and I’m open to suggestions on how they might be tweaked or improved. I tried to cover all of the major types of spells, but with D&D spells being able to do so many different things I couldn’t cover everything, so let me know in the comments if you have any additional questions. If there are enough questions or requests, I might make a follow up video.

If you liked this video make sure to give it a like, and leave a comment to let me know if you want to see more D&D homebrew stuff in the future. If you want to see more of my stuff make sure to subscribe, and check out the rest of the channel where I have a bunch of videos on various game design topics. And join me next time, where I will be taking a look at how the creature designer works in Spore! Until then, thank you so much for watching and I’ll see you next time.