How is the proficiency bonus calculated for a multiclass character?

Proficiency bonus depends only on total character level, not on individual class levels. It equals 2 plus the floor of (total level minus 1) divided by 4, so it is plus 2 at levels 1 to 4, plus 3 at 5 to 8, and rises by one every four levels up to plus 6 at level 17.

How does multiclass spellcasting determine spell slots?

You add full caster class levels in full, half of your half-caster levels (Paladin, Ranger) rounded down, and a third of your third-caster levels (Eldritch Knight, Arcane Trickster) rounded down. That sum is your effective caster level, which you look up on the Player's Handbook multiclass slot table.

Why does a Fighter 5 / Wizard 3 not get level-4 wizard slots?

Only the Wizard 3 counts toward caster level for a standard Fighter, giving an effective caster level of 3 and the slots a third-level caster has. The Fighter levels add hit points, attacks, and proficiency but no caster levels unless it is the Eldritch Knight subclass, which counts as a third caster.

How is Warlock handled?

Warlock uses Pact Magic, which does not combine with the normal multiclass slot table. Its slots are tracked separately, are all the same level, and recharge on a short rest. The tool flags this so you do not accidentally merge Pact slots into your regular spell slots.

Does total level cap at 20?

Yes, standard 5e characters cap at level 20, and the multiclass caster level used for slots also caps at 20. If your entered levels sum above 20 the tool warns you and caps the caster level and slot lookup at the level-20 row.

D&D Multiclass Proficiency & Spell Slot Tracker

Multiclassing in D&D 5e tangles two things that are easy to get wrong: your proficiency bonus, which tracks total level, and your spell slots, which follow a special combined caster-level rule. This tracker takes each class and level and returns your total level, proficiency bonus, effective multiclass caster level, and the full combined spell-slot table.

How it works

Proficiency comes from total level, while spell slots come from a weighted caster level fed into the Player’s Handbook multiclass table:

proficiency  = 2 + floor((total level − 1) / 4)
caster level = Σ full levels
             + floor(half-caster levels / 2)
             + floor(third-caster levels / 3)
slots        = PHB multiclass slot table[caster level]

Full casters (Bard, Cleric, Druid, Sorcerer, Wizard) count every level. Paladin and Ranger are half casters, and the Eldritch Knight and Arcane Trickster subclasses are third casters. Warlock is the exception — its Pact Magic stays separate and recharges on a short rest.

Example and notes

A Fighter 5 / Wizard 3 has a total level of 8, so a proficiency bonus of plus 3. Only the Wizard contributes caster levels here, giving an effective caster level of 3 and the spell slots of a third-level caster: four first-level and two second-level slots. Swap the Fighter to an Eldritch Knight and the math changes, because the subclass adds a third of its levels to the caster total. Always track Warlock Pact slots on their own, and remember the table caps at caster level 20.