The documentation below covers the basic usage of d20. But if you need help, have questions, or want to leave feedback, please email me at

If you like d20, please consider sharing it and rating it on the Mac App Store. This independent app developer will appreciate it. ;-)

Rolling dice

In d20, you make a dice formula then roll it to see the result. The dice roll formula is shown in the text field at the top of the window. Click on a die button to add it to your roll formula. Or type a roll directly into the text field.

Once you have finished making your roll formula, click Roll (or press CMD+Enter) to roll it. The result will appear in the result pane.

If the roll formula field has keyboard focus, you can simply press Enter to roll.

Dice roll formulas and custom dice

Since the dice roll formula is just text, you are free to edit it with the keyboard. You can type “4d20” to roll four twenty-sided dice, for example. You can also roll an any-sided die—type “3d11” to roll three eleven-sided dice. You can roll an any-sided die with up to 1000 sides.

Dice roll formulas are mathematical expressions, so you could type “2d12 / 2” to roll two twelve-sided dice and divide the result by two. You can use parentheses to control the order of operations. Typing “(1d20 + 4) * 2”, for example, would roll a twenty-sided die, add four to the result, and then multiply that by two.

Dice and modifier buttons

The buttons panel to the right provides a quick way to add commonly-used dice to your roll formula. Clicking the d20 button twice, followed by clicking the +2 button, would result in a dice roll formula of “2d20 + 2”.

Clicking Subtract enables subtraction mode—any die or modifier button you click while subtraction mode is on will be subtracted instead of added.


The results pane shows a running log of all your rolls. Each result shows the total along with a breakdown of each die result. Critical hits and misses are highlighted in color.

Results are cleared every time you quit the app. You can click Clear Results at any time to erase all the results.


Presets are dice roll formulas that you can save and re-use. To save a preset, first construct your dice roll formula. Next, click the + icon in the presets pane to add the current formula as a preset. Finally, name your preset and click OK.

Click on a preset to automatically make it the current roll formula (then click Roll to roll it).

When you hover over a preset you will see a button for deleting that preset and a handle that lets you drag-and-drop to reorder your presets.

The first ten presets can be activated by keyboard shortcuts (Option+1 for the first, and so on, with Option+0 being the tenth).

You can export your presets to add them to another Mac. See the Settings section for more information.


Click Settings to go to the Settings screen.

Dark Mode

Dark Mode is on by default. It presents the user interface as light text on a dark background. Uncheck Dark Mode if you would prefer dark text on a light background.

Import/Export presets

If you have presets, you will see a text field with an export code. You can copy this text and save or share it however you like. On another Mac, paste it into the import field and click Import Now to immediately add all the presets. Importing will erase any existing presets you have.