Spending and Gaining Points

Instead of gaining a number of spell slots to cast your spells from the Spellcasting feature, you gain a pool of spell points. You expend a number of spell points to create a spell slot of a given tier, and then use that slot to cast a spell. You can't reduce your spell points total to less than 0, and you regain all spent spell points when you finish a long rest.

You also regain a number of spent spell points when you finish a short rest, as shown in the Spells and Spell Points by Level table.

Spells of 3rd tier and higher are unusually taxing to cast. You can use spell points to create one slot of each tier of 3rd or higher, but after that, the cost of spell points needed to create another slot of the same tier is doubled until you finish a long rest.

Casting spells of 9th tier is extremely taxing. After casting once, the cost is quadrupled instead of doubled, though it still returns to normal after finishing a long rest.

Number of Points

The number of spell points you have to spend is based on your level as a spellcaster, as shown in the Spells and Spell Points by Level table. Your level also determines the maximum-tier spell slot you can create. Even though you might have enough points to create a slot above this maximum, you can't do so.

The Spells and Spell Points by Level table applies to bards, clerics, druids, sorcerers, and wizards. For an artificer, paladin, or ranger, halve the character's level in that class (rounding up) and then consult the table. For a fighter (Eldritch Knight) or rogue (Arcane Trickster), divide the character's level in that class by three (rounded up).

Formulas

The highest-tier spell a "full" spellcaster (bard, cleric, druid, sorcerer, wizard) can cast is equal to half its level (rounded up) to a maximum of 9th tier. It has a number of spell points equal to its level multiplied by the tier of the highest-tier spell it can cast.

It regains a number of spell points equal to the tier of the highest-tier spell it can cast when it finishes a short rest, and all of its expended spell points when it finishes a long rest.

A "halfcaster" (artificer, ranger, paladin) takes its level and divides it by 2 (rounded up) to determine the spellcaster levels, while a "thirdcaster" (granted by some subclasses) divides that number by three (rounded up) instead of by 2.