What is Frank Karsten's land formula?

Frank Karsten, a Magic pro and mathematician, derived a near-linear relationship between a deck's average mana value and the number of lands it should run. For a 60-card deck the guideline is roughly 16.37 plus 3.42 times the average mana value, with adjustments for cheap card advantage and ramp.

How do cantrips and ramp change the count?

Cheap card-draw and cycling cards smooth your draws, so the model trims about one land per three such cards. Ramp sources and modal double-faced lands that can be played as lands count as roughly half a land each toward your effective land base.

Does this work for Commander or Limited?

Yes. The base formula was derived for 60-card Constructed, so the tool scales the result linearly to a 40-card Limited deck or a 100-card Commander deck. Commander mana bases also depend heavily on color requirements, so treat the figure as a floor.

Is the recommendation a hard rule?

No. It is a statistically grounded starting point. Aggressive decks that want to curve out flawlessly may run slightly more lands, while combo decks that win from the hand can sometimes run fewer. Use the flexible range as your tuning window.

Why does a higher average mana value need more lands?

A deck full of expensive spells must reliably reach higher mana totals, which requires hitting land drops for more consecutive turns. More lands raise the chance of an uninterrupted mana progression, so the formula adds lands as the average mana value rises.

MTG Land Count Optimizer

How many lands should your deck run? The honest answer is “it depends on your curve” — and Frank Karsten turned that intuition into a formula. This optimizer applies his model, adjusts for cheap card advantage and ramp, and scales the result to your format so you get a defensible land count instead of a guess.

How it works

The core of the model is Karsten’s near-linear fit for a 60-card deck:

lands (60-card base) = 16.37 + 3.42 * average mana value

The tool then applies two modifiers before scaling:

Cheap cantrips and cycling smooth your draws and effectively replace themselves, so the model subtracts about one land per three such cards.
Ramp sources and modal double-faced lands add mana or double as lands, so each counts as roughly half a land toward your effective land base.

After applying the modifiers, the adjusted 60-card figure is scaled linearly to your chosen deck size — multiply by 40/60 for Limited or 100/60 for Commander. The result is rounded and clamped to a sensible range, and the tool also shows a flexible window of plus or minus one land for tuning.

Example and notes

A 60-card midrange deck with an average mana value of 2.5 and no cantrips or ramp lands at the base figure of about 24.9 lands — round to 25, and the flexible range spans 24 to 26. That lines up with the conventional 24-to-25 land recommendation for typical 60-card decks.

Keep in mind:

The base formula assumes a reasonably normal curve. Decks with extreme curves should also check the MTG Mana Curve Analyzer for a second opinion.
Color requirements matter enormously in multicolor and Commander decks. This tool sizes your land count but not the color split — make sure each color is represented enough to cast your spells.
Treat the recommendation as a launch point, then test and adjust based on how often you flood or get screwed in real games.