Created a level 10/10 Bladesinger/Eldritch Knight for fun, noticed the character had up to 5th level spells (due to level 10 wizard) but he has one 6th level spell slot and one 7th level spell slot. I am guessing this is due to both classes having spellcasting ability using the same ability score, but wondering if the extra high level spell slots are a bug or working as intended
By multiclassing rules, a Wizard 10/Eldritch Knight 10 has the spell slots of a 10 + (10/3 round-down) = 10 + 3 = 13th level full caster, so that's why you have the higher level slots. You can't learn or prepare spells of that level but you can upcast with the slots.
Spell Slots.You determine your available spell slots by adding together all your levels in the bard, cleric, druid, sorcerer, and wizard classes, half your levels (rounded down) in the paladin and ranger classes, and a third of your fighter or rogue levels (rounded down) if you have the Eldritch Knight or the Arcane Trickster feature. Use this total to determine your spell slots by consulting the Multiclass Spellcaster table.
If you have more than one spellcasting class, this table might give you spell slots of a level that is higher than the spells you know or can prepare. You can use those slots, but only to cast your lower-level spells. If a lower-level spell that you cast, like burning hands, has an enhanced effect when cast using a higher-level slot, you can use the enhanced effect, even though you don’t have any spells of that higher level.
For example, if you are the aforementioned ranger 4/wizard 3, you count as a 5th-level character when determining your spell slots: you have four 1st-level slots, three 2nd-level slots, and two 3rd-level slots. However, you don’t know any 3rd-level spells, nor do you know any 2nd-level ranger spells. You can use the spell slots of those levels to cast the spells you do know — and potentially enhance their effects.
Created a level 10/10 Bladesinger/Eldritch Knight for fun, noticed the character had up to 5th level spells (due to level 10 wizard) but he has one 6th level spell slot and one 7th level spell slot. I am guessing this is due to both classes having spellcasting ability using the same ability score, but wondering if the extra high level spell slots are a bug or working as intended
Character sheet here in case that helps:
https://www.dndbeyond.com/profile/Strongfoot/characters/52023367
By multiclassing rules, a Wizard 10/Eldritch Knight 10 has the spell slots of a 10 + (10/3 round-down) = 10 + 3 = 13th level full caster, so that's why you have the higher level slots. You can't learn or prepare spells of that level but you can upcast with the slots.
Helpful rewriter of Japanese->English translation and delver into software codebases (she/e/they)
As per the Multiclassing rules rom the PHB (https://www.dndbeyond.com/sources/phb/customization-options#Spellcasting):
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