Online Dice Roller

Roll any dice, with the modifiers that matter

Set the number of dice and how many sides they have, add a modifier, and roll. The tool writes the standard dice notation for you as you change the form, so you can copy it into a character sheet or a chat window.

Every roll comes from crypto.getRandomValues() — your operating system’s entropy pool. Nothing is sent anywhere, and nothing is stored.

Dice notation

Notation is the shorthand tabletop players already use. You can type it directly into the notation field instead of using the form.

Notation	Meaning
3d6	Roll three six-sided dice
d20	Roll one twenty-sided die
3d6+2	Roll three d6 and add 2
1d20-1	Roll one d20 and subtract 1
2d20kh1	Roll two d20, keep the highest — advantage
2d20kl1	Roll two d20, keep the lowest — disadvantage
4d6dl1	Roll four d6, drop the lowest — ability scores
4d6dh1	Roll four d6, drop the highest

Dropped dice stay visible in the result, crossed out, so you can see the whole roll and not just the part that counted.

Advantage and disadvantage

In D&D 5e, advantage means rolling two d20 and taking the better one; disadvantage means taking the worse. It is not the same as a flat bonus — it shifts the shape of the distribution rather than the whole range.

With advantage, your average d20 result rises from 10.5 to about 13.8, and the chance of rolling 15 or higher goes from 30% to 51%. Near the middle of the range the effect is worth roughly +5; at the extremes it is much smaller, because you still cannot beat a 20 or fall below a 1.

Rolling ability scores

The classic method is 4d6dl1: roll four six-sided dice, drop the lowest, sum the rest. Repeat six times, once per ability.

That gives an average of about 12.24 per score rather than the 10.5 you would get from 3d6, and it makes very low scores rare — you would need three 1s or 2s in a row for the dropped die not to help.

One d20 or three d6? They are not the same shape

Both cover a range, but they behave completely differently — and picking the wrong one is a common mistake when people design house rules.

A d20 is flat. Every value from 1 to 20 comes up 5% of the time. A 1 is exactly as likely as a 10. That makes it swingy: outcomes at the extremes are common, which is why it suits a single dramatic check.

3d6 is a bell. The sum runs 3 to 18, but the middle dominates — 10 and 11 together account for 25% of all rolls, while 3 and 18 together account for 0.9%. Extremes are nearly forty times rarer than the middle.

	d20	3d6
Shape	Flat	Bell
Most likely result	any, 5% each	10 or 11, 25% combined
Chance of the extreme	5% for a 20	0.46% for an 18
Feels like	Luck	Competence

Swap a d20 for 3d6 in a system and you have not adjusted the difficulty — you have changed how often the unlikely happens at all. Add more dice and the bell narrows further: 10d6 almost never strays far from 35.

Why a browser roll is fairer than a real die

A physical die is a manufactured object. Pips are drilled out, which removes a little material from one face; injection-moulded dice cool unevenly; cheap dice are noticeably lopsided. Casino dice are ground to tight tolerances and have flush, painted pips precisely because ordinary dice are not fair enough.

This tool has no faces to be uneven. It draws from the same entropy source your browser uses for cryptography, and it maps that entropy onto your dice range using rejection sampling — so no face is even slightly more likely than another.

Where dice rolls get used

• Tabletop RPGs — attacks, saves, ability scores, damage
• Board games — when the dice are lost or you are playing remotely
• Teaching probability — roll 1,000 dice and watch the distribution appear
• Deciding — highest roll picks the restaurant

Frequently asked questions (FAQ)

How many dice can I roll at once?

Up to 1,000 in a single roll, with up to 10,000 sides each. The limits exist to keep the page responsive, not because the maths runs out.

Are the rolls really random?

Yes. They come from crypto.getRandomValues(), a cryptographically secure generator seeded by your operating system. The mapping onto the dice range uses rejection sampling, so there is no modulo bias favouring low faces.

Can I keep or drop more than one die?

Yes. Set "how many" next to the keep/drop option, or write it in the notation — 6d6kh3 keeps the highest three of six.

Are my rolls saved anywhere?

No. Rolls exist only on screen. Reload the page and they are gone. If you need a roll somebody else can verify, use the seeded mode in the random number generator and share the certificate.

Why is the dropped die still shown?

So you can see what actually happened. A result of 14 from 4d6dl1 means more if you can see it came from 6, 5, 3 and a dropped 1.