Enter the number of cards North-South are missing in Suit 1 and Suit 2, then click “Calculate” to show percentages of all possible breaks. For example, suppose North-South have eight spades and seven hearts. For Suit 1 enter 5 (missing spades), and for Suit 2 enter 6 (missing hearts). It makes no difference which suit is 1 or 2. Optionally, Suit 2 may be left blank to analyze a single suit.

Spaces — By default, percentages are calculated a priori (from the beginning) which assumes West and East have 13 available spaces each. Reducing one or both settings can find true percentages for any situation. For example, suppose that in another suit West is known to hold six cards and East only two; set West’s spaces to 7 and East’s to 11 to analyze this scenario.

Known — By default, all breaks are presumed to be possible. If you know otherwise, you can exclude layouts. Suppose East opened 1 NT, and you conclude he cannot have a singleton or void. On the “Known” line, type “E1>1 E2>1” (no quotes). You may also wish to add “E1<6 E2<6” to exclude 6+ cards.

Syntax of first character: W or E; second character: 1 (Suit 1), 2 (Suit 2), S (sum Suit 1+2), D (difference Suit 1-2) or R (reverse difference Suit 2-1); third character: = (equal), ! (not equal), > (greater than) or < (less than). This must be followed by a number 0-13. Letter case doesn’t matter. Multiple tests must be separated by a space (logical And is assumed); checking “Or” will interpret as alternatives; and “Not” will reverse true/false status.

Precision — By default, percentages are rounded to two decimal places. This can be increased to 4, 6, 8, 10 or 12 places, or decreased to 0 (rounded to whole percent).

Theoretical notes — This analyzer works for any missing cards within two groups, regardless of how those groups are defined. For example, if you are missing three kings and two queens, enter 3 and 2 (for Suit 1 and Suit 2) to determine correct percentages for the division of those honors.

For an explanation of how known information affects the calculation of percentages, see How Percentages Change.