Given the possible dice rolls, totals and sub-totals you choose, this
calculates the odds of rolling any combination you want in the game of
backgammon.
It is designed more as a learning tool for beginners, to get an idea
of the odds of certain roll combinations, than as something to use on
every roll (which would make your play so slow it would probably drive
your opponent nuts).
I was inspired to write it because I've been in situations where I
thought, "I wonder what the odds of that happening were..."
Try an example
The panels
There are five panels. Each has a set of toggle buttons, and three
buttons to select all, none, or invert the current selection. The
All panels buttons act on every panel at once, and the
Both dice buttons act on Die 1 and Die 2 together.
- Die 1 and Die 2
-
The values allowed for each die. The two dice can come up in either
order, so Die 1 = 6 means "at least one die is a 6". Choosing values
here enables or disables the buttons on the other panels.
- Total
-
The totals you want to allow. For example, a roll of 5 and 3 totals
8.
- Sub-total
-
The sub-totals you want to allow. For the roll of 5 and 3, the
sub-totals are 5 and 3. For a double 4 they are 4, 8 and 12, and the
total is 16. A roll counts if its total or any of its sub-totals is
selected. Choosing values on the Total and Sub-total panels enables
or disables the buttons on the Rolls panel.
- Rolls
-
Each button is a possible roll. For example, "2 1 = 3" is a roll of
2 and 1, which totals 3. A roll of 1 and 2 is the same, so there is
only one button for it.
Using the buttons
- Click or tap a toggle to select or deselect it.
-
Shift+click a toggle, or press Shift+Enter or Shift+Space, to select
only that value in its panel. On a touch screen, press the panel's
None button, then tap the value.
-
With the keyboard, Tab moves between groups of buttons, and the Left
and Right arrow keys move within a group. Home and End go to the
first and last button.
-
Dashed, faded buttons are values that can't happen with your current
choices.
The result
The chance of rolling any of the selected rolls is shown as a fraction
of 36, in lowest terms, and as a percentage. The page address records
your choices, so you can bookmark or share a set-up.
About
. Developed by Evan MᶜLean.
Copyright © 2003–2026 Evan McLean. Released under the BSD 3-Clause
licence.
Licence text