The page opens with two ordinary dice, which is what most lessons need. Everything else is one button away: the pencil beside ROLL adds dice up to twelve and gives each one its own type and color, Fullscreen throws them across the whole screen, and the space bar rolls without you having to find the mouse. If your classroom display is a Chromecast or a Google TV, the dice can land there instead of on your laptop.
On this page
Free, with no account and no ads
There is no sign-in and no paid tier. Open the page and press ROLL. That works during a lesson, during a meeting, or on a substitute's laptop that has never seen the site before. Nothing about the dice changes if you come back tomorrow or next term.
The page carries no advertising, which matters on a projector: whatever is on the classroom screen is seen by thirty people, including anyone walking past the door. The free Android app that puts the dice on a TV is free in the same way, with no ads, no purchases, and no account.
Always the same starting point. This page opens with two plain six-sided dice every time, whatever you set up last lesson. Change the dice for the task at hand, and next time you open it you are back to two, with no leftover d20 from Friday's probability lesson.
Fullscreen, sound off, space bar to roll
Four small things make the difference between a dice roller and a dice roller you can actually teach with:
- Fullscreen. The button under ROLL hides the page and fills the screen with the dice. Press it once at the start of the lesson.
- Sound on or off. The dice make a rolling sound by default. The speaker button next to Fullscreen mutes them, and your choice is remembered on that computer, so the cart laptop stays quiet after you have muted it once.
- Space bar rolls. Press the space bar (or the R key) to roll without hunting for the button, which is handy when the laptop is on the desk and you are at the board. Both work whenever the dice are on screen and you have not clicked into a button or a link. Scroll the dice out of view and the space bar goes back to being the scroll key.
- The total, and the faces. Once the dice settle, the readout above the button shows the total and the individual faces, so the number the class calls out is written down for them. The result is also announced as text for screen readers.
One more, for games rather than lessons: tap or click a die to hold it, and it sits out the next roll while the others tumble. That is how a class plays anything in the Yahtzee family on one screen.
Cast the dice to the classroom TV
Plenty of rooms now have a television on the wall rather than a projector, and a laptop tethered to it by an HDMI cable that somebody has to unplug at the end of the hour. If that TV is a Chromecast, an Android TV, or a Google TV, you can skip the cable: install the free Android app on your phone, tap the cast icon, and the dice roll on the TV while the phone stays in your hand.
Two details to know before you plan a lesson around it:
- Casting comes from the Android app, not from this web page. The page itself rolls in a browser; the app is what talks to the TV.
- Samsung and LG smart TVs do not have Chromecast on board. Those need a Chromecast plugged into an HDMI port first. An Android TV or Google TV can also run the app directly, with the remote, and no phone at all.
Walking around the room with the dice in your pocket changes how the activity feels: you can hand the phone to a student, and the roll everyone is watching is theirs.
Twelve dice, and a color for each group
The pencil button beside ROLL opens the dice manager. Add dice up to twelve, remove them again, and give every single one its own type and its own color from a palette of nine, or a custom color you mix yourself. The dice keep their colors from roll to roll.
Colors turn one roll into several at once. Three red dice for the red group and three blue for the blue group settle in the same throw, and each group reads only its own. The same trick covers sorting and comparison tasks: two colors, one roll, and the class compares the pairs instead of waiting through six separate throws.
Fewer dice, bigger dice. Up to six dice all stay at full size on screen. Past six the view pulls back to fit them all in, so each die is drawn smaller. If the back row is squinting, take dice off the table rather than adding them.
Real d4 to d20 for probability lessons
The pencil gives you the whole polyhedral set as well as the six-sided die, and every one of them is a 3D model that tumbles and lands on a face. You can mix types in a single roll, which is useful for a lesson: put a d6 and a d12 on the table together and roll them a few dozen times.
| Die | Faces | Useful for |
|---|---|---|
| d2 | 1 to 2 | A coin flip that lands on the table with everything else. |
| d3 | 1 to 3 | Three-way choices; shows pips, so it reads the same from any angle. |
| d4 | 1 to 4 | The pyramid with no top face. The roller reads the corner numbering for you. |
| d6 | 1 to 6 | The everyday die, with pips rather than digits. |
| d8 | 1 to 8 | Eight groups, eight tasks, eight numbers on the board. |
| d10 | 1 to 10 | Place value and tens; the 10 is printed as a 0, as on a physical d10. |
| d12 | 1 to 12 | Comparing a flat spread with the hump of two six-sided dice. |
| d20 | 1 to 20 | Percent-style questions, and the die every role-playing group knows. |
| d% | 00 to 90 | The tens die; roll it with a d10 to get a number from 1 to 100. |
| Fudge | + / − / blank | Two plus, two minus, two blank faces, counting as +1, −1 and 0 for work on a number line. |
What each shape is, and why a die has to be a regular solid to be fair, is spelled out on the page about types of dice.
Ways teachers use it
These are the jobs a die has always done at the front of a classroom, without the die that rolls off the desk and under the radiator.
- A probability demo the class can watch. Two dice, roll thirty times, tally the sums on the board, and the pyramid appears: the 7 comes up six times as often as the 12, because there are six ways to make it and one way to make a 12. The full distribution (every sum, every count) is on the dice probability page, and you fill the tally chart with the roller.
- Expected value, felt rather than told. The average of a single die is 3.5, a number that never appears on any face. Roll long enough with the class keeping a running average and it drifts toward 3.5 in front of them.
- Picking a group or a turn order. Number the groups and roll the die that matches (a d6 for six groups, a d8 for eight). The class can see that the choice was not yours.
- Mental math on tap. Two dice and an instruction: add them, multiply them, subtract the smaller from the larger. Twelve dice and a race to add them all before the roller's total appears.
- A five-minute game at the end of the hour. Pig needs one die and teaches when to stop pressing your luck; its classroom cousin Skunk is played by the whole class at once on a five-column grid. More of them, sorted by age, are on the dice games for kids page, and the full set of rules pages is in the dice games overview.
What this roller can't do
Better to know before the lesson than during it. This is a dice roller, and it stops at the edges of what dice are:
- No custom faces. You cannot put words, letters, math operators, or pictures on the dice. Each type of die is a 3D model with its markings built into the geometry, so the roller can only show what those models carry. If you need story dice, alphabet dice, or an add-and-subtract die, buy blank write-on dice or use a tool made for custom faces. A cheap workaround: roll a numbered die and keep a numbered key on the board, so 1 is who, 2 is where, 3 is when.
- Twelve dice, and no more. Twelve is a hard cap, not a setting. A task that needs twenty dice needs two rolls.
- It only rolls dice. There is no name picker, timer, group generator, or on-screen score sheet. If you want a score sheet you can print, a few of the game pages have one, for instance the Shut the Box page.
- The web page cannot cast by itself. Sending the dice to a TV is the Android app's job, as described above.
- It needs a working internet connection. The 3D engine loads from the web, so a machine that is fully offline will not render the dice. When that happens the page tells you and gives you a plain text roller instead, so you still get your numbers.
Frequently asked questions about the classroom dice roller
Is the classroom dice roller free?
Yes. It is a web page you open and use: there is no account to create, no trial, no limit on how many times you roll, and no ads on the page. The Android app that casts the dice to a TV is free as well.
How do I get the dice big enough for the whole class to see?
Press Fullscreen under the roll button and the dice fill the screen with the rest of the page hidden. On a projector or an interactive panel that is usually all you need. If your classroom display is a Chromecast, an Android TV, or a Google TV, the free Android app can send the dice to it from your phone instead.
How many dice can the classroom roller show at once?
Between one and twelve. The pencil button beside the roll button opens the dice manager, where you add or remove dice and give each one its own type and color. Twelve is a hard limit, so a task that needs more dice has to be split across two rolls.
Can I put words, letters, or math symbols on the faces?
No. Every type of die here is a 3D model with its markings built into the model itself, so the roller can only show the faces those models carry: pips, numbers, the percentile tens, and the plus, minus, and blank of a Fudge die. For word or letter dice you need blank write-on dice or a tool built for custom faces. The free workaround is to roll a numbered die and keep a numbered key on the board.
Which dice can I use for a probability lesson?
The pencil button offers a d2, d3, d4, d6, d8, d10, d12, and d20, plus a percentile tens die and Fudge dice. You can mix them in one roll, so a class can watch the spread of two six-sided dice next to the spread of a single twelve-sided die.
Does it work on a Chromebook or an interactive panel?
It runs in the browser, so any Chromebook, laptop, tablet, or interactive panel with a current browser and an internet connection can open it, and nothing gets installed. If the 3D dice cannot load, the page says so and falls back to a plain roller that still gives you the numbers.