Tabletop and Board Game Calculators
4d6 drop lowest calculator.
See the exact odds for each ability score when you roll four six-sided dice and keep the highest three. Change the numbers to compare other methods, and see the chance of getting a high score somewhere in a set of six. Runs in your browser.
Roll method
Odds
Enter your numbers above.
Answer
Rolling 4d6 and keeping the highest three gives an average of 12.2446 per score, against 10.5 for straight 3d6. The chance of any one score being 15 or higher is 23.15%, and the chance that at least one of six scores is 15 or higher is 79.40%.
Worked example
Of the 1,296 equally likely outcomes of four six-sided dice, 21 give an 18 (three sixes kept), so a single 4d6 drop lowest score is 18 with probability 21 / 1,296 = 1.62%. For a 15 or higher the chance per score is 23.15%; across six scores the chance that at least one reaches 15 is 1 - (1 - 0.2315)^6 = 79.40%.
How it works
The method. The Basic Rules character-creation chapter says to roll four 6-sided dice and record the total of the highest three, then repeat five more times to get six numbers. This tool enumerates every ordered outcome of the dice, sorts each, adds the highest K and counts the totals.
Several scores. Scores are rolled independently, so the chance at least one of S scores reaches the target is 1 - (1 - p)^S and the chance that all S reach it is p^S, where p is the single-score chance.
Other methods. Set dice rolled and kept both to 3 for straight 3d6, or change the sides and counts to compare house variants. The calculation is limited to 2,000,000 outcomes (for example up to 8 six-sided dice).
Sources and basis (opened 2026-10-08): Basic Rules, Chapter 1: Step-By-Step Characters (D&D Beyond) for the four-dice, keep-highest-three method; counts by full enumeration of all outcomes, checked in the test suite.
FAQ
What is the average of 4d6 drop lowest?
12.2446, compared with 10.5 for 3d6. That is about 1.74 points higher per score.
What are the odds of rolling an 18 with 4d6 drop lowest?
1.62%, or 21 of 1,296 outcomes. The lowest possible score is 3, with 1 outcome of 1,296.
How likely is it to roll at least one 18 in six scores?
9.34%.
Is 4d6 drop lowest better than 3d6?
Yes for high scores. Dropping the lowest die raises the average and makes very low scores rarer, but it also makes the spread narrower.
Can I use this for other roll methods?
Yes. Set the number of dice rolled, how many highest dice you keep and the die size, as long as the total number of outcomes stays under 2,000,000.
Disclaimer
Fan-made math tool, not affiliated with or endorsed by the publishers of any game named on this page.