Four mana

Mana probabilities

How often will your deck have the mana it needs?

MAGIC: THE GATHERING

Your deck

No mulligans. Commander uses 99 cards and a turn-one draw.

4 mana by turn 463.2%

36.8% chance of being short.

Average first turn5.23

with enough mana

First turn at 75%6

chance of enough mana

Chance by turn

Choose a bar to inspect it
24 lands / 60 cards · on the play 75% reference

One land play per turn. Each land enters untapped and makes one usable mana. No ramp or extra draws.

Exact values & calculation
Chance of having enough mana by turn
Turn Probability

We count draws without replacement using the hypergeometric distribution:

P(X ≥ k) = Σ C(L, x) C(N − L, n − x) / C(N, n)

N is deck size, L is lands, n is cards seen, and k is lands needed. The sum includes every possible x ≥ k. A known opening hand is removed before counting future draws, and its lands are subtracted from the number still needed.

The average includes long waits. The 75% figure is the first turn at which at least three quarters of hands have enough mana. Neither measures whether you have drawn the spell itself. Colors, tapped lands, mulligans, ramp, extra draws and a game ending are outside this model.

Why “four mana is five”?

With 24 lands in 60 cards, you miss your fourth land by turn four in about 37% of random hands on the play. Most hands get there on turn four; the late ones pull the average to turn 5.23.

A five-mana spell needs another land after that. Under the same assumptions, reaching 75% reliability takes until turn eight. Raise the mana requirement above to see how quickly the wait grows.

THE ORIGINAL ARTICLE

In Development — The Deadly Four-Mana Mark

Alexander Shearer · ChannelFireball · April 4, 2012

This is the article behind the idea. Shearer examines the time needed to reach higher mana costs. The probabilities and averages in this calculator are computed here; “four is five” is a paraphrase.