Complete guide
Online dice roller: fair rolls, totals and probability
Choose how many dice to roll, select d4 through d100 and add an optional modifier. Calculator24 rolls instantly, shows every die, calculates the total and creates a reproducible link for that exact roll.
How to use the dice roller
Select the number of dice and sides, enter a positive or negative modifier if your game uses one, then press Roll dice. The large result is the final total; the breakdown preserves the individual rolls and their subtotal.
- Choose 1 to 100 dice.
- Select d4, d6, d8, d10, d12, d20 or d100.
- Add a modifier or leave it at zero.
- Press Roll dice again whenever you need a new result.
Dice notation explained
Standard dice notation uses NdS: N is the number of dice and S is the number of sides. Therefore 2d6 means two six-sided dice, while 1d20 means one twenty-sided die.
A suffix changes the total. In 2d6+3, roll two d6, add them, then add 3. Calculator24 keeps the raw subtotal and modified total separate so the arithmetic can be checked.
NdS = N dice with S sidesfinal total = Σ rolls + modifierHow random rolls are generated
When a new roll is requested, the page obtains a 32-bit seed from the browser's Web Crypto getRandomValues method. The W3C specification requires this method to use a cryptographically strong source of random values provided by the user agent.
The seed drives the visible sequence and is included in shared links. Opening that link reproduces the same roll, which is useful when players need to verify what was shared. Pressing Roll dice creates a new seed and a new sequence.
Dice totals and probability
A fair S-sided die has S possible faces. The probability of one specific face is 1/S, and its expected average is (S+1)/2. With N independent identical dice, multiply that average by N and then add the modifier.
Totals are not equally likely when several dice are added. With 2d6, seven is more common than two because six ordered combinations produce seven, while only one produces two.
P(specific face) = 1 ÷ Sexpected total = N × (S + 1) ÷ 2 + modifierCommon dice rolls
Six-sided dice are common in board games. Polyhedral d4, d8, d10, d12 and d20 dice are widely used in tabletop role-playing games. A d100 roll is often represented by percentile dice and returns 1 through 100 here.
Limits and responsible use
The roller supports at most 100 dice per action so every individual result remains inspectable and exportable. A modifier changes only the final total; it never changes a die face.
A browser roller cannot provide the physical controls, certification or independent audit required by regulated gambling. Use a system approved for that purpose when money, prizes or legal compliance depend on the outcome.
Dice types and possible single-die results
| Die | Possible result | Expected average |
|---|---|---|
| d4 | 1–4 | 2.5 |
| d6 | 1–6 | 3.5 |
| d8 | 1–8 | 4.5 |
| d10 | 1–10 | 5.5 |
| d12 | 1–12 | 6.5 |
| d20 | 1–20 | 10.5 |
| d100 | 1–100 | 50.5 |
Frequently asked questions
Can I roll two dice online?
Yes. Set Number of dice to 2 and choose the number of sides. For two standard dice, select d6.
What does 2d6 mean?
It means roll two six-sided dice and add their face values. The unmodified total ranges from 2 to 12.
Is each shared roll reproducible?
Yes. The shared Calculator24 link includes the roll seed and settings, so it recreates the same sequence.
What is a dice modifier?
A modifier is a fixed number added to or subtracted from the sum after all dice are rolled.
What is the average result of a d20?
The expected average of one fair d20 is 10.5. Any individual roll is still an integer from 1 through 20.
Can this roller be used for gambling?
It is intended for games, education and simulations. It is not a certified or independently audited gambling device.
What to keep in mind
This browser-based roller is suitable for games, classroom exercises and simulations. It is not a certified gambling device and should not be used where audited randomness is required.
Results display up to 8 decimal places; exported numbers preserve calculation precision. This is a calculation summary, not an official certificate.