Magic the Gathering Land Calculator
Input the total number of non-land pips and the number of lands needed
Example 1: For a Golgari (black/green) deck with 28 black cards and 33 green cards, and 39 lands.
Estimated, 17 swamps (black), 21 forests (green), and 1 color of your choosing.
Example 2: For a Golgari (black/green) deck with 12 black cards, 25 green cards, 26 black/green cards, and 37 lands.
Divide the number of multi-color cards among the single color cards as you see fit.
For an even split, 26/2 is 13, 12+13 => 25 black cards, 25+13 => 38 green cards.
Estimated, 14 swamps (black), 22 forests (green), and 1 color of your choosing.