D4 Dice Roller
The d4 is a tetrahedron: four triangles, and no face pointing up when it lands. You read the result either at the apex or along the bottom edge, depending on how the die is numbered. Players call it the caltrop, mostly because of what it does to a bare foot at two in the morning.
Press Roll to throw the dice.
Press Space to roll again. Type notation like 2d6+3 or 4d6dl1 straight into the box.
Recent rolls
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A d4 has 4 faces numbered 1–4. On a fair die every face is equally likely, so any single result comes up 25% of the time. Rolls run from 1 to 4, the average is 2.5, and the standard deviation is 1.12. The shape it is built from is the tetrahedron.
- Minimum
- 1
- Maximum
- 4
- Mean
- 2.5
- Median
- 2.5
- Std deviation
- 1.12
- Chance per face
- 25%
d4 probability
One die is flat. There is no curve and no middle to aim for, because each face has exactly one way to come up out of 4 possible results, so nothing is more likely than anything else. Add a second die and that changes immediately: totals start piling up in the middle. The dice probability guide works through why.
| Total | Ways | Probability | This or lower |
|---|---|---|---|
| 1 | 1 | 25% | 25% |
| 2 | 1 | 25% | 50% |
| 3 | 1 | 25% | 75% |
| 4 | 1 | 25% | 100% |
When you'd roll a d4
Reach for a d4 when the swing needs to be small but not trivial. It is the die for light weapons, minor spell effects, and short duration counters, and it shows up in random tables with only four entries: a direction, a season, a suit. Some players keep an elongated barrel-shaped d4 in the bag instead of the pyramid, because it actually rolls rather than sticking where it lands.
Common uses
- dagger and dart damage in D&D 5e
- healing potion dice
- bardic inspiration at low levels
- Magic Missile damage in D&D, where each dart rolls its own small die
- Guidance, Resistance and other cantrips that add a small bonus to a check
- Counting down a shrinking resource in a game that steps a die size at a time
d4 questions
How do you read a d4?
Two numbering styles exist. On apex-read dice the same number appears at the top point of all three visible faces, and that is your result. On bottom-read dice you read the numbers sitting flat along the base edge facing you. Check which style your die uses before your first roll.
Why is a d4 called a caltrop?
A caltrop is a spiked device that always lands with one point up, used for centuries to stop horses and later tyres. A tetrahedron does the same thing. Anyone who has walked across a dark room after a game night understands the nickname without further explanation.
Does a d4 roll fairly?
A well made tetrahedron is fair, since all four faces are identical triangles. The practical problem is that it barely tumbles, so a short toss can be predictable. Roll it hard against a wall or a dice tray edge rather than dropping it flat on the table.
What is a crystal or barrel d4?
It is a stretched four-sided die shaped like a long prism with pointed ends. Four numbered faces run down the length and you read the one facing up. It rolls much further than the pyramid version, which is the whole reason people buy them.