Calculator · mana

The turn you can count on, computed rather than asserted. The grid meets every mana cost with every turn and gives the chance that you can cast it; under it you build one card — its cost, its coloured pips, and the lands of each colour in your deck — and it says the turn that card really arrives, and which half of the cost kept it waiting.

What this assumes

• 40 cards, 17 of them lands, on the play.
• No card draw and no mulligan. A cantrip or a hand you sent back would move the numbers; neither is counted.
• Ramp only if you ask for it. Set it to none and the figures are the chapter’s assumption. Set it to one to four and the deck holds that many two-mana sources, each adding one mana from the turn after it is cast, cast as soon as you hold one and have two mana, one a turn. That is a mana creature; a land-fetch at three mana would be slower, and a card that only fixes colours is not ramp at all.
• One land a turn, and every land you draw gets played. So “six lands by turn seven” means six lands have arrived among the cards you have seen, not that you chose to play them.
• Cards seen by your turn N: seven in the opening hand plus one for each turn after the first — so 7 + (N − 1) on the play, and one more on the draw.
• The figure itself is the hypergeometric chance of holding at least that many lands among those cards — the share of all possible deals that give you enough — and the rule that you may play only one land a turn, which is why a cost can never be paid before the turn that matches it however many lands you have drawn. It is computed exactly, not simulated.
• Colours, when you ask for them. Split the lands between two colours and give the cost its pips, and the figure becomes the chance of holding enough mana and enough of each colour — the same exact arithmetic, over a deck divided four ways: sources of the first colour, sources of the second, lands that make neither, and spells. A land that makes both colours is not in it, nor is a cost spread over three, and the ramp setting is left out of the coloured answer.

Your card, and your lands

Where each number comes from

This calculator shows the arithmetic behind Mana, and the drill that asks you to use it is Casting Speed.