MTG Mana Base Calculator
How many sources of each color do you actually need to cast your spells on time? Enter your deck size, the color demand of a spell, and the turn you want to cast it. The calculator returns exact hypergeometric odds and a recommended source count.
What a mana base actually is
Most players count lands. Serious deckbuilders count sources of each color. Your land total tells you how often you will hit your land drops. Your color source count tells you how often those lands will produce the colored mana your spells demand on the turn you actually want to cast them. Those are different questions with different answers.
A 24-land deck with 14 blue sources is not the same as a 24-land deck with 10 blue sources. A three-color Commander deck with 38 lands is not the same as a three-color Commander deck with 38 lands where the third color has 9 producers. The lands look identical on a spreadsheet. The games do not.
Rules of thumb by format (starting points, not answers)
These are reasonable starting land counts before the calculator refines them for your specific curve:
- Limited (40-card): around 17 lands for a normal two-color deck.
- Aggressive 60-card: 17 to 18 lands, sometimes fewer with cheap card selection.
- Midrange 60-card: 24 to 25 lands.
- Control 60-card: 26 to 27 lands.
- Commander (99-card): 36 to 38 lands for most builds, moved down with heavy ramp or up with fewer mana rocks.
Those numbers answer how often will I hit lands. The calculator on this page answers the harder question: how often will the right colors be there when I need them.
Reference chart: sources by format and pip count
Before you touch a single input, this is the shape of the answer. Every cell is the number of sources of one color that first reaches a 90% success rate for a turn-4 cast, on the play, from a 7-card opening hand with no mulligan. The bars are scaled across the whole chart, not per row — the Commander row towering over the other two is the point.
| Deck size | Single pip | Double pip | Triple pip |
|---|---|---|---|
| 40 cardsLimited | 89 by turn 3 | 1314 by turn 3 | 1719 by turn 3 |
| 60 cardsConstructed | 1213 by turn 3 | 2022 by turn 3 | 2629 by turn 3 |
| 99 cardsCommander | 2022 by turn 3 | 3336 by turn 3 | 4448 by turn 3 |
Three things worth reading off it:
- Deck size moves the count, not the ratio. A single pip wants about 20% of your deck producing that color in all three formats — 8 of 40, 12 of 60, 20 of 99. A double pip wants about a third of the deck, a triple pip a bit over 43%. The Commander numbers look alarming next to the Limited ones, but they are the same requirement rescaled to a bigger deck.
- The second pip is the expensive one. In a 60-card deck the first pip costs 12 sources and the second costs 8 more; a third only adds 6. That front-loaded jump is why a card, not a 2 card, is usually the one pinning your mana base.
- A triple pip in Commander is a color-identity decision. 44 sources of one specific color is more mana than a typical 37-land, ten-rock deck has in total — and colorless rocks produce none of it. If a triple-pip card is a deck's centerpiece, that deck is mono-colored or close to it, and no amount of fixing changes the arithmetic.
Treat every cell as a starting point, not a verdict. Push the cast turn one later and each number drops; ask for 85% instead of 90% and they drop again. That is what the calculator above is for — set your own deck size, pip count, turn, and threshold and read your real number.
How to use this calculator
- Set your deck size (99 for Commander, 60 for Constructed, 40 for Limited — it opens on Commander).
- Pick a specific spell in your deck that you want to cast reliably — the one with the tightest color demand is the one that pins your mana base.
- Enter the number of colored pips of that color (1 for , 2 for , 3 for triple-pip).
- Enter the turn you want to cast it.
- Enter how many sources of that color your deck currently runs.
- Read the odds. If you are below your comfort threshold, either add sources or push the cast turn one later.
A worked example
The calculator above already opens on one: a 99-card Commander deck, a single-pip spell you want on turn 3, on the play, with 20 sources of that color. It reports 88.1% and recommends 22 sources — so as built you miss on curve about one game in eight, and two more sources of that color close the gap. That is the whole loop: read the odds, compare to the recommendation, decide whether the two slots are worth it.
Now make it hard. Keep the deck at 99 and change the cost to a double pip () on turn 4, and say you have 24 green sources — a healthy count for a two-color deck. The calculator returns 75.3% and asks for 33 sources. That is not a rounding error you can patch with one more Forest; it means the card is only reliable in a deck where green is clearly the dominant color. Reading that number early is worth more than any amount of tuning later, and it is the single most common way a mana base that looks fine on a spreadsheet fails at the table.
The credit line for the math
The general project of solving Magic mana bases with the hypergeometric distribution was popularized by Frank Karsten's mana base research. His articles are the best further reading if you want the theory behind the numbers. Every value on this page comes from that same distribution, and none of it is copied from a published table: the calculator computes your numbers live as you type, and the reference chart above was generated by running this page's own calculator code at a 90% threshold.
FAQ
Does a single pip need fewer sources than a double pip?
Yes. A single-colored cost like only needs one blue source in your opening cards. A double-pip cost like needs two. Because you are asking for two specific matches instead of one, the required source count grows much faster than intuition suggests. The calculator shows the gap numerically.
Why does a Commander deck need so many more sources than a 60-card deck?
Because the same requirement is spread over a bigger library. Drawing a specific color out of 99 cards is harder than out of 60, so the count has to rise to compensate — but the proportion barely moves. A single pip wants roughly 20% of the deck producing that color at any size, a double pip about a third, a triple pip a bit over 43%. The reference chart above shows all three formats side by side. Where Commander genuinely does get harder is the top row of that chart: 44 sources of one color in a 99-card deck is more mana than most decks run in total, which is why heavy triple-pip cards push you toward mono-color.
Does being on the play or on the draw change the number of sources I need?
Slightly. On the draw you see one extra card by the same turn, which raises your odds a few percentage points. For most decks it does not change the recommended source count by more than one, but you can toggle it above.
How do ramp and card draw affect the calculation?
The base calculation assumes a normal draw step per turn. Ramp and extra card draw effectively let you see more cards by your target turn, which improves your odds. A useful shortcut is to set the target turn one higher than the actual cast turn to approximate the effect of one ramp or draw spell.
What about mulligans?
The math assumes a 7-card opening hand with no mulligan, which is the honest floor. Real players mulligan when the opener is unkeepable, so actual reliability is a bit higher than the numbers shown — especially in Commander with the free first mulligan.