How would you Homebrew upcasting cantrips?

[Thrasher92]

I am very aware that, by the book, you cannot use a higher level spell slot to cast cantrips because they do not use a spell slot.

However, would you allow a player to use a spell slot to give a cantrip more power? If so, what rules would you use to allow it?

I've been thinking about adding just 1 or 2 dice to the damage if they want to use a 1st level spell slot for a cantrip. Roleplaying wise I think it makes sense that they should be able to "pour more energy" into the spell, enough to expend a spell slot.

What do you think?

[clash]

I would just scale it one more dice per spell level. Be very careful with Eldritch Blast though. Don't scale by another ray per slot. Say something like "The first ray increases it damage by 1d10 per spell slot level"

[Spectrulus]

I would not, as it tends to favor casting Cantrip with spell slots over spells for damage purposes.

For example, a strong level 1 spell, Ice knife, hits for up to 1d10+2d6 for a 1st level slot, at all levels.

An upcast toll the dead would use a first level slot for up to 2d12, which makes it almost equal one a single target at level 1.

At level 5, the upcast Toll the Dead would hit for 3d12, making it a much better use of a 1st level slot for single target damage.

Maybe an item that lets a player upcast a Cantrip 3 times a day requiring Attunement is as far as I would recommend going.

[HappyDaze]

I think that it should be possible to make a leveled spell with a cantrip as a prerequisite. Using the leveled spell slot effectively allows for an upgrade of the cantrip. I have never quite seen such a thing, but it is theoretically possible.

[Chronos]

Strictly speaking, it is possible to cast a cantrip from a spell slot. A cantrip is a spell you know, and you can use a spell slot to cast any spell you know. It just doesn't provide any benefit in the vast majority of cases.

One of the few exceptions is Light, which you might want to upcast in order to defeat a Darkness spell.

[Tiadoppler]

My advice:

Make it weaker than a paladin's smite (and other class-specific abilities that use up spell slots do deal damage). If it's a generally available option for all spellcasters, it should add only 1d4 damage per spell level, and only to the first damage dealt by the spell (no extra attacks for Eldritch Blast, for example). It shouldn't usually be the most efficient use of a spell slot.

Make it cost something to get the option. Maybe it could be a feat, a sorcerer metamagic, or a major feature of a new sorcerer subclass.

I could imagine writing a new cantrip that specifically allows upcasting. It shouldn't have a great damage type, or scale very well. Here's a rough draft:


Rising Flame
Evocation cantrip

Casting Time: 1 action
Range: 30 feet
Components: V, S, M (a lump of coal)
Duration: Instantaneous

A burst of flame engulfs a creature you can see within range. The target must succeed at a Dexterity saving throw or take 1d6 fire damage.
This spell's damage increases by 1d6 when you reach 5th level (2d6), 11th level (3d6), and 17th level (4d6).
At Higher Levels. When you cast this spell as an action, you can choose to expend a spell slot of 1st level or higher. If you do so, the spell's damage increases by 1d6 for each slot level. You must choose to whether or not to expend a spell slot before the target rolls their saving throw.


This cantrip seems safely lower in power than most actual spell options (a cantrip shouldn't outshine a high level spell), but could fit a niche for a caster who doesn't want to learn or prepare low level attack spells.

[Millstone85]

Strictly speaking, it is possible to cast a cantrip from a spell slot. A cantrip is a spell you know, and you can use a spell slot to cast any spell you know.When a class gives you spell slots, it is "to cast your spells of 1st level and higher". I am pretty sure that 0th-level spells are not supposed to be upcastable.

[SpawnOfMorbo]

I would not, as it tends to favor casting Cantrip with spell slots over spells for damage purposes.

Personally, I'm very ok with the idea that all damaging spells are cantrips (work with the cooler higher level concepts) and leave spell slots to the more niche options non-damaging options.

[KillingTime]

I generally think that upcasting cantrips is a bad idea for game balance.
Spell options are strictly limited by design, and the player makes their choice of cantrips and levelled spells based on the knowledge that they need to cover various bases and maintain tactical flexibility.
If cantrips can be upcast this need is removed as suddenly your firebolt can cover all your options.

[SpawnOfMorbo]

I generally think that upcasting cantrips is a bad idea for game balance.
Spell options are strictly limited by design, and the player makes their choice of cantrips and levelled spells based on the knowledge that they need to cover various bases and maintain tactical flexibility.
If cantrips can be upcast this need is removed as suddenly your firebolt can cover all your options.

Firebolt covering all your needs for a single target ranged fire damage spell is a good thing. It gets rid of bloat.

Why have something that does the same thing? Just allow firebolt to be searing ray when upcasted.

This opens you up to broadening your spell choices when you go to pick spells because now you don't need to pick a spell that is just firebolt but "more".

[Bjarkmundur]

I wouldn't
But you could probably use the psionic disciplines as a blueprint to create a pretty interesting spell system,


Resistance
Divination Cantrip (Cleric)
Casting Time: 1 action
Range: Touch
Component: VS
Duration: Concentration, 1 minute

You touch one willing creature. Once before the spell ends, the target can roll a d4 and add the number rolled to one saving throw of its choice. It can roll the die before or after making the saving throw. The spell then ands.

At Higher Levels: When upcast with a spell slot of 1st level of higher the spell's effects are replaced with the effects of another, more powerful spells.
1st level slot: Bless (three targets)
2st level: Warding Bond
3rd level: Beacon of Hope
4th level: Aura of Purity