How Many Sorcery Points Should This Homebrew Metamagic Cost?

Question

I'm back with another homebrewed thing. But, I can't decide on a reasonable cost for it. See below:

Sharpened Spell

You spend X Sorcery Points. You modify a spell with a range that is not Self or Touch, has a casting time of 1 action, and a duration of Instantaneous.

The spell you cast changes in the following ways:

• If the spell forces a save DC, roll a spell attack instead. You deal 0 damage on a miss. If you hit, multiply the damage dealt by 1.25
• If the spell is not single target, it becomes a single target spell. If the spell has area effects, it only affects the single target of the spell. If it also deals damage, multiply the damage by 1.5

The idea is to maximize the damage dealt by turning your normal spell into an attack spell against a single target -- basically trying to turn every spell into Disintegrate.

Justification of 50% Damage Boost

So that people don't pass too quick a judgement off this as possibly "too powerful" or "too weak," I'd like to break down the numbers here.

I based the 50% damage increase off of the One Target vs Multiple Targets table in the DMG.

DMG pg. 284

Spell Damage

Spell Level	One Target	Multiple Targets
Cantrip	1d10	1d6
1st	2d10	2d6
2nd	3d10	4d6
3rd	5d10	6d6
4th	6d10	7d6
5th	8d10	8d6
6th	10d10	11d6
7th	11d10	12d6
8th	12d10	13d6
9th	15d10	14d6

The DMG says you can create a new spell with damage appropriate for its level by keeping the mean value of its damage around the same as the mean values of the dice shown in the Spell Damage table.

DMG pg. 283

Spell Damage

You can use different damage dice than the ones in the table, provided that the average result is about the same. Doing so can add a little variety to the spell. For example, you could change a cantrip's damage from 1d10 (average 5.5) to 2d4 (average 5), reducing the maximum damage and making an average result more likely.

On average, the mean values for single target spells according to that table is 50% higher than multiple target spells, so to compensate for the fact that this spell forces a multi-target spell to become a single-target one, the damage is scaled up by that amount.

Justification of 25% Damage Boost

If saving from a spell successfully causes you to take half damage, then its maximum possible damage is 25% weaker. The Spell Damage table assumes you take half damage on a successful save, but advises increasing the damage by 25% if targets take no damage from a save.

DMG pg. 283

Spell Damage

For any spell that deals damage, use the Spell Damage table to determine approximately how much damage is appropriate given the spell's level. The table assumes the spell deals half damage on a successful saving throw or a missed attack. If your spell doesn't deal damage on a successful save, you can increase the damage by 25 percent.

Since this spell forces you so that your targets take no damage if your attack roll misses, I compensate by boosting damage up 25%

Closing Remarks and Dilemma

This metamagic changes the way the spell is cast while trying to abide by fair tradeoff rules according to the DMG. This probably gives it a minimum cost of at least 1 SP (and not a higher minimum) because the trade off is fair.

However, it does have a significant benefit. It replaces save DCs with spell attack rolls. This lets you use things like Advantage and Inspiration on your roll to boost your attack. It is not necessarily a strong effect, but with the right party/preparation, I think it can be.

My dilemma is, I can't decide the appropriate total SP cost. I can't seem to find a spell that provides similar advantages to form a basis.

Remembering that 1 spell slot = 1 SP, how many SP should this metamagic cost?

Answer 1

How many Sorcery Points should this cost? Lots. At least 5, since this metamagic is better than Careful Spell, Empowered Spell and Heightened Spell combined. I'm sure you can see where I'm going with this - it's too powerful to put a realistic cost on it.

Your new metamagic option does 3 things. The first is pretty simple - it multiples damage by 1.25, or 1.5 if it's an AoE spell. I'm going to look at Fireball (a pretty classic damage spell) as a standard example.

A Fireball does 8d6 damage, averaging 28 damage. An Empowered Fireball, assuming a Charisma of 20, does 8d6 with the option to reroll up to 5 dice, for an average of 31.75 damage. A Sharpened Fireball does 8d6 * 1.5 damage, for an average of 42 damage.

At this point, you might be thinking "But Fireball does 8d6 damage, where the entry in the Spell Damage table for a 3rd-level spell is only 6d6!" Unfortunately, the advice in the Spell Damage table bears little or no resemblance to the spells that were actually published.

Note that this is also the case for single-target spells. Disintegrate (which uses a saving throw, not an attack roll) deals 10d6 + 40 (average 75), Empowered Disintegrate deals 10d6 with up to 5 rerolls + 40 (average 78.75), and Sharpened Disintegrate deals (10d6 + 40) * 1.25 (average 93.75).

At any rate, hopefully you can see how Sharpened Spell is considerably more powerful than Empowered Spell.

Moving on, the second thing Sharpened Spell does is change the target making a saving throw into the caster making an attack roll. Ostensibly, this is a loss in damage, since most (though not all) spells that use saving throws deal half damage on a successful save. However, it is far easier to make an attack roll hit than it is to make an enemy fail their saving throw.

Firstly, it's a trivial matter to give yourself advantage on an attack roll; it's an extremely non-trivial matter to give an enemy disadvantage on a saving throw. For example, you have inspiration, True Strike, the Help action, the Hide action, The Wild Magic Sorcerer's Tides of Chaos, and heaps of other things to give yourself advantage on a roll. To give disadvantage, you have Heightened Spell, or Contagion. There's not many, and they require significantly more expensive resources than the advantage options.

Secondly, most powerful monsters (the kind that would be worth sharpening a spell for) have Legendary Resistance, which makes it impossible to make them fail their saving throws, since they can just say they didn't. You can make them burn through their uses of this feature, but if they're smart they'll only use it on your best spells.

Finally, attacks are (by design) easier to hit. Everyone uses attacks, and some characters use them exclusively, so monsters can't be impossible to hit without making some players feel useless. On the other hand, not everyone uses saving throws, and everyone can still function without them. It's difficult to prove this mathematically, but anyone can quickly observe that there are extremely few monsters with AC above 20.

A mid-level sorcerer (let's say level 8) with maxed Charisma only needs to roll 12 or higher to hit an AC of 20. With advantage, which you'd better believe they'll find a way to get on their Sharpened Fireball, that's a 69.75% chance to hit.

The same sorcerer casting a regular Fireball has a save DC of 16. Let's assume the monster isn't great at Dexterity saving throws (but not too bad at them, either) and give it a +3. It has a 60% chance of failing that saving throw, which is pretty good odds for the sorcerer, but not as good as the attack roll. On the other hand, if the monster gets advantage on the saving throw (which there are a lot of ways for it to do), it has a 36% chance of failing. Not so good. And, of course, this is assuming a monster with really good AC, which is more of a worst-case scenario than a usual one.

So that's why Sharpen Spell is also better than Heighten Spell. The third thing Sharpen does is change the spell from an AoE to a single-target. This looks like a drawback, and often will be, but in those situations the sorcerer just won't do it. For the sorcerer to be thinking about Sharpening a spell, they'll have a priority target in mind. This lets them use Fireball on the Big Bad without having to worry about hurting their allies. "But they could just use a single-target spell!" Well, they could. But they have a limited number of spells known, and there are in fact no 3rd-level single-target spells. Hence, this is also better (or at least as good as) Careful Spell, albeit only when you have a priority target.

With all that out of the way, this is a really cool idea. It gives us back the Spellwarp Sniper from 3.5, which was great. Focusing Fireballs into concentrated beams of destruction? Awesome.

I strongly recommend going ahead with this, but removing the damage bonuses. If your players choose to use this, they know they're turning an AoE spell into a single-target spell, and they know they're adding a chance of total failure. They'll use it when those aren't problems, so you don't need to boost it because of those drawbacks.

With that change in place, I'd recommend this metamagic option costing 3 sorcery points, the same as Heightened Spell. Wait, what? I said earlier that it was better than Heightened Spell! Well, it is, but it requires the player spending additional resources to make it that way. It's trivial to give yourself advantage on an attack roll, but it's not free. You have to spend an inspiration point, or use your previous turn to cast True Strike or to Hide, etc.

Answer 2

I agree with the analysis in the other answer, but recommend taking it the other direction: remove the first ability entirely but keep the damage boost.

The sections of the DMG you've cited clearly show that converting a multi-target spell to single-target and adding damage is trivial and not (inherently) OP. Turning save spells into attacks, however, would be difficult to balance and would become more OP at higher levels when players have more ways to get advantage. You would possibly have to make the SP cost based on spell level.

Also, I wouldn't make my players do the effort of multiplying numbers together; that would be a deal-breaker for some. Instead, use the underlying principle in the cited table. Several of the entries effectively convert d6s to d10s, so do that. Because the DMG recommends using fewer dice when converting spells beyond 4 damage dice, the sorceror will see a slight damage jump after this point – an additional 5.5 damage on average – but sorcerers typically won't use SPs until they have 3rd level spell slots, and by that point the players are fighting single-target monsters that have over 100 HP.

Using this for status-effect-imposing area spells would normally be wasteful, since you would get fewer targets for the status effect and since those spells typically have less damage to buff. As you've suggested, this is basically a way to turn Fireball into (a weaker) Disintegrate without having Disintegrate in your list of known spells. IMO, this is worth 1 SP.

Sharpened Spell

You spend 1 Sorcery Point to focus the energy in a spell, increasing it's damage. Choose a ranged spell that could damage multiple creatures:

• If the spell is an area spell, decrease the size of its effect area to a 5ft cube
• If the spell is a targeted spell with multiple targets, choose a single target

Adjust the damage by replacing d6s with d10s (e.g. Fireball's 8d6 becomes 8d10)