Build Commander
There isn't one right number. A spellslinger deck can run a dozen and a go-wide deck can run thirty, and both can be correctly built. Here's how to find the range for your deck instead of a deck in general.
Unlike lands or ramp, creature count isn't a fixed slot in the deck template. It's downstream of your archetype: a deck built to go wide with tokens and a deck built around a handful of spells and a Voltron commander both look completely different on this axis, and both can be right.
What matters more than hitting a specific number is making sure your creature count matches what your deck is actually trying to do. A go-wide deck with only 12 creatures doesn't have enough bodies to go wide with. A spellslinger deck with 30 creatures has crowded out the spells that were supposed to be the plan.
See the full archetype guide for the twenty Commander archetypes this range table is built from, each with its own defining cards and commanders.
Start from what wins you the game. If your win condition is combat damage, you need enough creatures to actually apply that pressure. If it's a spell-based combo or a direct-damage plan, creatures are support, not the point, and the count should reflect that.
Count token generators as more than one card. A single Rin and Seri or a Krenko, Mob Boss can put several bodies on the battlefield from one card in hand, so a go-wide deck's real "creature count" during a game is usually well past its printed card count.
Leave room for the rest of the template. Every creature slot is a slot not spent on ramp, draw, or removal. A deck that's pushed its creature count to 35 to maximize a tribal payoff has to find those cuts somewhere else, and the mana base and interaction suite are the wrong place to shrink first.
18-25 is the range most midrange, value-oriented decks land in, which covers a large share of decks built without a hyper-specific archetype in mind. Outside that shape, the right number depends entirely on what your deck is trying to do.
Yes, if it has no way to interact with the board otherwise. A deck with almost no creatures needs a real plan for blocking and closing games (efficient removal, a fast combo, direct damage), or it's simply going to lose races it has no way to contest.
Not as printed cards in your 99, but they matter more than the raw count suggests. A go-wide deck with 20 creature cards can regularly field 30+ actual creatures at the table because several of those cards make more than one body. Count your token generators as a multiplier on your creature count, not as separate from it.
It's one more creature on the battlefield in most games, so it's worth factoring in when you're judging how the deck actually plays, even though it lives in the command zone rather than your 99.
The Deck Lab's blueprint measures your list against the template your archetype actually wants, not a one-size-fits-all number.
Open the Deck Builder