Are there rules on how to research and create new spells?

Question

I was thinking about making a few new spells for 5th ed D&D. Are there any official guidelines on how to go about doing so? If so where is the information found? Please note: I am interested only in 5th ed, no other edition's materials.

In reading through the question How can I let my PCs create new spells in a balanced and fair way? various advice is given but not about the mechanics around the development of the spell itself from the DM's and game design perspective.

The reason why I say that the question does not answer my question is because damage is covered, but not range nor spell shape specifically. Casting time is covered but the information seems a bit disjointed. And not everything is about damage, either. There's nothing in any of the answers concerning how long non damaging spells should last (or take to cast). Also nothing about how to determine if new spells should require concentration or not

Answer 1

There are no rules specifically for custom spell research in 5e.

That being said, there are some guidelines. Chapter 9 of the Dungeon Masters Guide has a section on Creating Spells, and Chapter 2 of Xanathar's Guide to Everything has a section on Scribing a Spell Scroll.

So, the short answer here is that this is something you'll have to work on with your DM.

Personally, that's not good enough for me. I want details!!...and my DM has plenty on his plate with our 8 person party (4 of which are multiclass bards, ugh!). So, when I find myself wanting something custom in the spell department, I homebrew a spell and submit it to him for approval. I go into a lot of detail on that process in my answer to this question: Homebrew spell for detecting resistances/vulnerabilities.

I'll summarize here:

• Find a spell that's similar to what you want.
• Next make a template of what the spell does. Range, damage, etc etc.
• Then decide what you'll need to change in that spell to make it perform the way you want.
  • If you're making lateral changes, like changing Fireball's fire damage to acid and making it rain down from overhead, you really aren't increasing it's power any, so just make the changes.
  • However, if you need to add something to the spell that it doesn't already do, that's a vertical change that increases its power, and you need to make the spell a higher level to keep it balanced. So if you want your new Acid Rain spell to have a 40 foot radius instead of 20 feet (or for it to Rain on the Astral Plane), you need to increase its level.
• Finally, you take your new spell and have a chat with your DM about why you want it.

And, before you sit down with your DM, feel free to post your new spell here and ask if it's balanced. I know I'd be happy to help you work that out!