Press “Roll Dice” to roll four twenty-sided dice at once; the total is between 4 and 80. The average total is 42 and the most likely total is 42 (3.34%).
Quick facts
- Dice
- 4 twenty-sided dice (4d20)
- Total range
- 4 – 80
- Average total
- 42
- Most likely total
- 42 (5,340/160,000 ≈ 3.34%)
- All the same
- 20/160,000 ≈ 0.013%
- Highest total (80)
- 1/160,000 ≈ 0.00063%
- Randomness
- Cryptographic, every face equally likely
4d20 total distribution
Four d20 have 160,000 equally likely outcomes. The extreme totals (4 and 80) can each be made only one way, while 42 can be made 5,340 ways — so the total clusters in the middle and extreme results are rare.
How do I roll?
- The dice roll automatically when the page opens. To roll again, press “Roll Dice”, tap the dice or hit the space bar.
- On a phone with “Shake to roll” enabled, just shake your device.
- Pick a die type from “Dice Types” in the top menu or the d4 – d20 tabs: roll 1–4 of a d4, d8, d10, d12 or d20, or 1–6 six-sided dice.
- Every roll is saved to “Roll History” with its total, and the “Stats” tab shows how often each face has come up.
Is Zar Salla a fair dice roller?
Yes. Results come from your browser’s cryptographic random number generator (Web Crypto API, crypto.getRandomValues), and rejection sampling gives every face exactly the same probability. Nothing is sent to a server, nothing is decided in advance and no roll depends on the previous one.
Just like real dice, short streaks of the same number are normal. As you roll more, each face’s share gets closer to the expected value — you can watch this yourself in the “Stats” tab.
How many d20 do you want to roll?
Frequently asked questions
What is the average of 4d20?
Each d20 averages 10.5, so 4 of them average 42.
What is the most likely total on 4d20?
42, with 5,340 of 160,000 outcomes (3.34%).
What are the odds that all four d20 match?
20/160,000 = 0.013%.
Last updated:
