Roll a D2: Two Sided Dice Roller
This free d2 roller is for players and game masters who need a fair two sided die: a coin flip written as 1d2. Tap to roll, set how many d2s you want and add a modifier if a ruling calls for one. Each face is equally likely, so the result is 1 or 2 with a 50% chance.
Tap the die to roll 1d2. Space and Enter work too.
Average for 1d2: 1.5 (before you roll)
How to use the d2 roller
Tap to roll. Press the big die and the roller shows 1 or 2. Space and Enter work too once the page has focus, unless you are typing in a box.
Set the count and modifier. One d2 is the default. Raise the count to roll a handful at once, then type a modifier to add or subtract after the dice are totaled.
Read every face. When you roll more than one d2, each face appears under the total. The average for your current notation is shown before you roll.
Need mixed dice or typed notation such as 1d2+1d20? Use the main DnD dice roller. To see exact odds for any pool, open the dice probability calculator.
What a d2 is used for
A d2 is not part of the standard seven-dice polyhedral set. It is the notation for a fair coin: two outcomes, same chance. Game masters reach for it when a scene should split even, such as which of two doors a wandering monster checks first, or which of two tied targets an effect picks.
Fifth edition rarely prints "1d2" on a weapon line. The value is still useful at the table whenever the rules, or a house call, ask for a 50/50 result without using a high-sided die and then reading even or odd by hand.
If you typed 1d2 in the main roller you would get the same two faces. This page exists so that query has its own roller, title and explanation. New to the bag? See what dice you need for DnD.
How to roll a physical d2
Most people do not own a two sided die. A coin works: pick which face is 1 before you flip. Any even-sided die also works if you agree that odd numbers are 1 and even numbers are 2. A d6 used that way is still fair, because three faces map to each result.
This virtual d2 roller returns the number the rules want, so you do not have to remember the mapping in the middle of a scene.
Average d2 roll and odds
Every face of a fair d2 is equally likely, so 1 and 2 each have a 50% chance. The average of one d2 is 1.5. Two d2s average 3 and range from 2 to 4. The full chart for larger counts lives on the probability page.
Virtual dice vs a coin or a stand-in die
A coin can roll under a book. A stand-in d6 asks everyone to remember odd and even. A virtual two sided roller shows a clear 1 or 2, a total with any modifier already added and a session average if you keep rolling.
Each roll here uses your browser's cryptographic random number generator, with extra values thrown out so no face is favored. See the about page for the method, or the dice roller FAQ for more on randomness and privacy.
More than a d2
A three sided check has its own d3 roller. A standard set starts at the d4 roller and includes the d6, d8, d10, d12, d20 and d100. Larger random tables can use the d1000 roller.
d2 roller FAQ
Is this d2 roller free?
Yes. It is free, with no ads and no sign up. Open the page on any device and roll.
What is the average d2 roll?
The average of one d2 is 1.5, which is (1 + 2) divided by 2. Each face has a 50% chance. Two d2s average 3.
What is a d2 used for?
A two sided roll is a fair coin flip written as dice notation. Tables use it to pick between two targets, split an even-or-odd call, or resolve any 50/50 choice the rules leave to chance.
How do you roll a d2 with a physical die?
Flip a coin and read heads as 1 and tails as 2, or roll any even-sided die and treat odd as 1 and even as 2. This roller skips that mapping and returns 1 or 2 directly.
Can I roll more than one d2?
Yes. Set the dice count above the result, then tap to roll. You can roll up to 20 d2s here. For a larger pool or mixed dice, use the main dice roller and type something like 6d2 or 1d2+1.
Is the d2 roll truly random?
Each dice roll draws random numbers from your browser's cryptographic generator. Values that would favor a face are thrown out and drawn again, so both faces have the same 50% chance.
See the Nat20 Roller FAQ for more on notation, advantage and how rolls stay random.