First, multiclassing is an optional rule. Under the default base rules, no multiclassing is possible at all (see p. 163 of the Player’s Handbook). Second, as Travis notes, you can only multiclass between different classes.
Do you allow Multiclassing?
Multiclassing is great, but it is OPTIONAL, and many player’s won’t use it. I play in, I am the only multiclassed character (fighter/barbarian).
Can the DM do whatever they want?
There are no limits. The DM can change anything and everything. The question is Should They? The DM needs to ask themselves if they SHOULD change a rule before changing it.
Can I multiclass twice?
By the rules you cannot. The rules for multiclassing state: With this rule, you have the option of gaining a level in a new class whenever you advance in level, instead of gaining a level in your current class.
How many levels can you multiclass?
Total limit of 20 levels of all your classes combined If you multiclass, you will have the same total level* as your single classed party members, just split between 2 (or more) classes.
Do you need a DM for multiclassing?
Whether or not your DM allows multiclassing, you will still want to read this D&D 5e multiclassing guide to understand why or why not. But the DM’s ruling is required before you can multiclass. They level up. They meet the ability score minimums. The prerequisites for a class involve having a minimum of 13 in the most relevant score for that class.
Do you need to read the D & D multiclassing guide?
Like feats and flanking, multiclassing is an optional ruleset. Whether or not your DM allows multiclassing, you will still want to read this D&D 5e multiclassing guide to understand why or why not. But the DM’s ruling is required before you can multiclass.
Do you need to know the rules for multiclassing?
Multiclassing is actually pretty simple. It looks confusing and the text in the Player’s Handbook has some gaps (which I’ll fix below), but if you understand the core rules of advancing a single-class character you don’t need to know much more to successfully advance a multiclassed character.
Do you need to let the DM know when you are?
Yes. The PHB p. 163 is explicit in that you have to have the GM’s permission. Prior to the game in this context means that you have to get permission from your DM before you use it in game. If you decide during your campaign or a session of the game and ask them to multiclass before it happens in-game and they give you permission, then that works.
