This calculator takes a CSV deck list and figures out how many of each basic land type should be put in based on the colored mana symbols on the spells, and it compensates for the types of mana that lands already in your decklist produce. It works great on decks of any size, although it saves the most time for larger decks such as Prismatic (5 colors, 250 cards). These decks contain ~100 lands and figuring the mana base is tedious. When a card or two is added or removed the mana base has to be completely recalculated!
1. In MTGO, load a deck in the Deck Editor. Visual mode should be off (the cards in your deck should be a text listing, not card images). If visual mode is on, click the small table icon next to the minimize button in the upper right of the Deck window.
2. Select all the cards in the deck (right click a card, choose "Select All"). Export the cards to a CSV file (right click a card, choose "Export as CSV"). Note where you save the file.
3. Click the Browse button in the calculator and open the CSV file. The decklist will be loaded into the calculator.
4. Enter the target deck size. This is the finished size you want your deck. Alternatively, you can enter what percentage of the deck you want to be land and the calculator will compute the target deck size for you.
5. The calculator instantly reports the number of basic lands that are recommended you add in order to meet the target deck size. It also displays other useful information to help with making mana base decisions.
1. Some cards require basic lands, such as certain spells (Explosive Vegetation, Anger, etc), fetch lands, tainted lands, etc. For these cases, place the minimum basic lands absolutely necessary in the decklist and uncheck "Exclude basic lands" so that basic lands in the decklist are not ignored.
2. Be wary when the calculator recommends none or only a few basic lands. Decks that only splash a color may need more land than reported.
3. Clicking a basic land box will disable computation for that color, distributing the basic land slots among the remaining colors.
4. You may want to adjust the calculator's results if you must have a color early or you don't need a color until later in the game.
5. The CSV data can be edited directly while in the calculator to see how different quantities of spells affect the recommended basic lands.