Mana base

How many lands of each color do you need to cast your spells on time?

Deck size

Sources of one color you need in the deck (lands that make it) to cast a card on its turn.
Color symbols	Turn 1	Turn 2	Turn 3	Turn 4	Turn 5	Turn 6
1 ({R})	16	15	13	12	11	10
2 ({R}{R})	27	24	22	20	18	17
3 ({R}{R}{R})	35	32	29	26	24	22

Example: a 60-card deck that wants {1}{R} on turn 2 needs the number in the first row, under Turn 2. A land that makes two of your colors counts for both. Exact math (hypergeometric) with a 7-card hand and no mulligans: a guide, not a guarantee.