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EDH advanced guide

Karsten manabase math for Commander

Updated

Frank Karsten's manabase math is a probability table that maps mana costs to the minimum number of colored sources needed to reliably cast the spell. For 37-land Commander, the cheat sheet: 1 pip = 12 sources; 2 pips = 17; 3 pips = 21. Miss those numbers and you get color-screwed on curve.

The Karsten table for Commander

Karsten's original work was for 60-card formats, but the Commander adjustment is simple: multiply his 60-card counts by (100/60) ≈ 1.67 for a first approximation. In practice we have well-established Commander tables:

  • ◆1 single pip (W, U, B, R, G) at CMC 2 → 12 sources
  • ◆1 single pip at CMC 3 → 11 sources
  • ◆2 pips (WW, UU, etc.) at CMC 3 → 17 sources
  • ◆2 pips at CMC 4 → 16 sources
  • ◆3 pips (WWW, UUU) at CMC 4 → 21 sources
  • ◆3 pips at CMC 5 → 20 sources

What counts as a source?

A "source" is any card in your deck that reliably produces that color of mana. That includes basic lands, dual lands, mana rocks (Sol Ring counts as 0 for this purpose since it doesn't make colored mana), and ramp spells that fetch a specific color.

A partial source (Yavimaya Coast makes U or G but only sometimes both) counts as ~0.75 sources for each color.

How to apply it

Go through your deck. For every spell, count the colored pips at every CMC. Then check the table. If your commander is Atraxa and you have 8 spells with WW at CMC 3, you need at least 17 white sources — count them.

  1. 01List every non-land spell and its cost
  2. 02Group by color and pip count
  3. 03Look up the required source count in the Karsten table
  4. 04Count your actual sources (lands + rocks) that produce each color
  5. 05If short, swap a land or add a source that fixes multiple colors

When to break the rule

If a spell is a wincon you need to cast on curve, it needs more sources than the table says. If it is a late-game finisher you can afford to hold, you can shave 1–2 sources.

Tutor-heavy decks can also shave sources — you have a 4th turn to find the missing color via Mystical Tutor / Vampiric Tutor.

Questions & Answers

FAQ

How many colored sources do I need in Commander?

For a single-color spell at CMC 2, run 12 sources of that color. For a double-pip spell like Counterspell (UU) at CMC 2, run 17 blue sources. For a triple-pip spell at CMC 4, run 21 sources. These are Frank Karsten's numbers scaled for a 37-land Commander deck.

What is Karsten's manabase rule?

Karsten's rule: for each spell in your deck, count the colored pips at that CMC and ensure you have enough sources to reliably cast it on turn X. The full lookup table is a two-axis grid of pip count vs CMC, with values calibrated to hit the spell 90%+ of the time.

Do I count mana rocks as sources?

Yes for colored rocks — Sol Ring is not a source for any color, but Chromatic Lantern, signets, and talismans all count as full sources for their colors. Sol Ring is a mana accelerator, not a color source.

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