Roll a d4: four-sided dice roller

How to use this d4 roller

Use the Dice selector to choose how many d4s to throw, from 1 to 6. The + and − buttons set a flat modifier, which is added to (or taken off) the total once, not to each die. Then press Roll, or pick the dice up with your mouse or finger and drop them in the tray.

Once the dice settle, the page shows each result and the total with the modifier included. The number that counts is the one at the top point, which is how most d4s sold today are read. A Potion of Healing in D&D, 2d4+2, is simply two dice with the modifier set to +2.

The tetrahedron: how to read a four-sided die

A d4 is a regular tetrahedron: four equilateral triangle faces, six edges and four corners, with three faces meeting at each corner. It is the simplest of the five Platonic solids. Because no two faces are parallel, it never lands with a face pointing up. One face always rests on the table and one corner points at the ceiling, so you cannot read it the way you read a d6.

Top-read d4s

Each face carries three numbers, one by each corner. When the die stops, the number at the top corner appears upright on all three visible faces. That is the result, and it is the system this online die uses.

Bottom-read d4s

On other designs the numbers sit along the middle of each edge, facing down. The result is the number printed along the base, again repeated on the three visible faces. This style was more common in older sets and is still made, so check your dice before a session: numbers at the points are read at the top, numbers along the edges are read at the bottom.

Is a d4 fair?

Geometrically, yes. Every face is identical and any face can be swapped for another by a symmetry of the solid, which is what makes each result equally likely. The weakness is physical: it barely rolls. It tends to stop almost where it lands, and metal ones often just slide. Players call it a caltrop because of how much it hurts to tread on. Makers sell blunted or elongated variants designed to tumble more.

What the d4 does in Dungeons & Dragons

In D&D 5th edition the d4 is the damage die for light weapons and a handful of support spells. According to the equipment tables in the free basic rules, in both the 2014 rules and the 2024 revision:

The monk has changed too. Its Martial Arts die started at d4 at 1st level in 2014 and starts at d6 in the 2024 revision. If your table mixes books, agree which figure you use before rolling.

The d4 in other games

Savage Worlds gives traits and skills a die type rather than a number, from d4 up to d12. The d4 is the bottom step: a character with d4 in a skill is barely trained and needs a 4 or better, the usual target number, which that die rolls only 25% of the time. Main characters also roll an extra d6, the Wild Die, and keep the better result.

Outside role-playing, a d4 settles any four-way choice: one of four players, one of the four seasons, or one of the four suits of a standard deck (spades, hearts, diamonds and clubs). Combined with a d6 (the d4 picks the block, the d6 the entry within it) it gives 24 equally likely results, handy for random tables.

d4 probability tables

On a single d4 every number comes up one time in four (25%). The average is 2.5. These are the chances of rolling a given number or higher:

Two d4s give 16 combinations and the total is no longer flat: 5 is the most likely sum.

For a Potion of Healing (2d4+2) just add 2 to the first column: healing 10 has a 6.25% chance and healing 7 or more, 62.5%. When you roll several d4s together, the chance that at least one shows a 4 grows like this:

A game example: the three darts of a 1st-level Magic Missile add up to 3d4+3, between 6 and 15, with an average of 10.5. The most likely totals are 10 and 11, each with 12 of the 64 combinations (18.75%).

History and curiosities of the tetrahedral die

Four-pointed dice are among the oldest known. In the Royal Cemetery at Ur, in present-day Iraq, Leonard Woolley excavated several boards of the Royal Game of Ur between 1922 and 1934, dated to around 2600-2400 BC. The game used tetrahedral dice with two of their four tips marked: you counted how many marked tips ended up on top. Each die therefore worked like a coin, with a 50% chance either way. One board is in the British Museum, whose curator Irving Finkel reconstructed the basic rules from a Babylonian clay tablet written around 177 BC.

In the Timaeus, Plato linked the tetrahedron with fire, the cube with earth, the octahedron with air and the icosahedron with water. Euclid devoted Book XIII of the Elements to constructing the five solids and proving there are no other convex regular polyhedra.

As a modern gaming die, the d4 reached hobby tables in the sets of five Platonic solids that Creative Publications, a Californian maker of maths teaching aids, began supplying in 1972. Wargamers bought them for the d20, and the earliest D&D rules called for the d4 only occasionally.

Practical tips for rolling a d4