D8 roller
Eight faces, one through eight.
Roll to draw new faces. Nothing is chosen yet.
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Recent rolls
Rolls you make in this visit show up here.
Each tap is a new pseudorandom draw via crypto.getRandomValues. Not atmospheric noise. How the draw works
About this page
An eight-sided die shows up in tabletop damage rolls and in classroom sets that want something between a cube and a d10. This preset fills in one d8. Each face from 1 to 8 has probability 1/8, or 12.5 percent. The expected value is 4.5. You can add more d8s and read the sum, but you cannot mix in a d6 without moving to the tray. An 8 on this die is not the same event as an 8 on a d10 or a d20. The denominators differ, so the probabilities differ. The page waits for Roll. A question mark is not replaced by a leftover demo value.
Related
Questions
How many outcomes are equally likely?
Eight. Listing them is the whole proof of the sample space: 1 through 8, one draw, inclusive. No face is wild unless your rule says so. If you need nine outcomes, this is the wrong die. Use the number tool and set the maximum to 9.
What is the average of a d8?
4.5. The sum of 1 through 8 is 36, and 36/8 is 4.5. Two d8s average 9, but the total ranges from 2 to 16 and the middle totals are more common. This page will show the individual faces so you can see the sum is not a single uniform draw.
Is an 8 here as likely as an 8 on a d10?
No. An 8 on a d8 is one of eight faces. An 8 on a d10 is one of ten. People compare the printed number and forget the die. If a rule says 'roll a d8,' stay on this page. If it says 'd10,' switch.
Can I change the preset after I open it?
Yes. The boxes are editable. The preset is a starting point, not a lock. If you change faces to 6, you are rolling a d6 on the d8 URL. That is allowed and a little confusing for anyone reading over your shoulder. Prefer the matching preset link when you can.
Does motion change the face?
No. Each roll is chosen when you press the button. Animation only reveals that draw. The browser uses crypto.getRandomValues and rejection sampling, which the methodology page spells out. This is not a loaded die, and it is not atmospheric noise. If your system asks for reduced motion, the shake is skipped and the number still appears. The accessible result is the text, not the animation.
How do I get back to every die type?
Use the dice roller link. That page lists d4 through d20, 2d6, and the tray. The header also has Dice. This URL stays useful as a direct d8 bookmark for a table that always wants eight faces.
What does a long series of d8 rolls look like?
Each face should claim roughly an eighth of the rolls, and the running average should wander around 4.5. Twenty rolls is a sketch, not a verdict. A face that is missing after twenty tries is still ordinary. Write the faces down if you are teaching the count. The on-screen strip only keeps the latest handful from this visit, so a worksheet is the record, not the browser. Do not add a modifier on this page. The tray is where a typed bonus belongs.