West and East spaces — By default, the percentages are calculated a priori (from the beginning) which presumes no knowledge of the East-West hands. You can find the true percentages for any situation by selecting the unknown “Spaces” for West and East. For example, suppose West is known to have six cards (in another suit) and East is known to have two. For West, select ‘7’ (the number of unknown cards) and for East, select ‘11’.
Precision — By default, the percentages are rounded to two decimal places. You can increase the displayed precision up to 12 decimal places if desired.
Theoretical note — This calculator works for any missing cards, regardless of whether they are in the same suit. For example, if you are missing three queens, selecting ‘3’ missing cards would give the correct percentages for the division of those cards.