You can simulate any standard die with repeated rolls of a fair D6. Some conversions are immediate, such as turning 1-2, 3-4 and 5-6 into a D3. Others use ordered odd-or-even rolls, and some require you to discard an unusable result and roll again. Follow the mapping consistently and the probabilities remain exact.
You only need one physical D6. When a method says to roll two, three or four D6s, you can roll the same die repeatedly and record the results in order. Several physical dice are simply quicker.
Pick the die you need. The tool will show the D6 method, the underlying rolls and the final result.
Choose a die above to see the method it uses.
D6 Conversion Table
| Target die | Minimum ordered D6 rolls | Exact method | Re-roll required? |
|---|---|---|---|
| D2 | 1 | Odd = 1, even = 2. | No |
| D3 | 1 | 1-2 = 1, 3-4 = 2, 5-6 = 3. | No |
| D4 | 2 | Two ordered odd/even rolls narrow 1-4. | No |
| D5 | 1+ | Keep 1-5 and re-roll every 6. | Yes |
| D8 | 3 | Three ordered odd/even rolls narrow 1-8. | No |
| D10 | 2+ | Generate D5, then add 0 or 5 with one odd/even roll. | Yes |
| D12 | 2 | First roll gives 1-6; second roll adds 0 or 6. | No |
| D16 | 4 | Four ordered odd/even rolls narrow 1-16. | No |
| D20 | 3+ | Generate D5, then add 0, 5, 10 or 15 with two odd/even rolls. | Yes |
| D100 | 4+ | Generate two D10 results as percentile digits; 00 = 100. | Yes |
The roll count is a minimum. A conversion marked with a plus sign may need additional rolls when a result is rejected.
Why the Order of the D6 Rolls Matters
When a method uses several D6 rolls, first, second and third are different jobs. The safest method is to roll one D6 repeatedly and record the results in order. If you roll several at once, use different colours or agree which die is first before rolling.
You can also agree to read them from left to right after they land, provided that convention is fixed before the roll. You must not decide which die was first once you can see the faces.
How Odd and Even Rolls Create D2, D4, D8 and D16
Odd covers 1, 3 and 5. Even covers 2, 4 and 6. Three faces each, so a single D6 read this way is an even choice between two options, and each choice halves the range that is left.
Worked example for a D8. Start with 1-8. An even first roll selects 5-8. An odd second roll selects 5-6. An even third roll selects 6. The final D8 result is 6.
D2 needs one division, D4 needs two, D8 needs three and D16 needs four. It is a plain way of counting in binary, though you need not think of it that way.
A second D4 method
There is more than one exact conversion. You can also roll one D6, keep 1-4 and re-roll a 5 or 6. That uses fewer rolls on average; the odd/even method always finishes in exactly two.
How to Roll a D3 With a D6
Roll one D6. A 1 or 2 is a 1, a 3 or 4 is a 2, and a 5 or 6 is a 3. Halving the D6 and rounding up says the same thing. For one official example, the current Warhammer 40,000 core rules define a D3 that way. The full breakdown is in What Is a D3 Die.
Why D5, D10 and D20 Need Re-rolls
Six equally likely results cannot be split into five equal groups. So for a D5 you keep 1-5 and re-roll every 6. A first attempt needs a re-roll one time in six, and repeated sixes are possible, so keep rolling until the result is between 1 and 5. Never turn the 6 into a 5.
D10 and D20 both contain a D5 component, so they inherit the same possibility. If the D5 part produces a 6, re-roll only that part. A group roll that has already produced a valid result can be kept, provided your agreed procedure identifies it without ambiguity.
If a custom D6 replaces the numeral 6 with a logo, that logo still counts as 6. Re-roll it whenever the method tells you to re-roll a 6.
Other unusual dice, such as D7 or D11, also need rejected outcomes when you use the simple universal method below.
How to Roll a D12 With Two D6s
The two dice do different jobs. The first gives a number from 1 to 6. The second decides the half: odd adds nothing, even adds 6. If the first roll is 4 and the second roll is even, the D12 result is 10.
How to Roll a D100 With D6s
Generate two D10 results independently using the method above. The first is the tens digit and the second is the units. In both, a result of 10 counts as 0, and 00 counts as 100.
So 4 and 7 give 47, a 10 then a 3 gives 03, a 4 then a 10 gives 40, and two tens give 100. This is a practical route built from the conversions already covered, not the only exact way to reach 100 results.
How to Roll Any Other Die With D6s
Find the power of two that is equal to or just above the number of faces you need. Generate that range with ordered odd/even rolls, keep the result if it falls within your die, and repeat the whole sequence if it is too high.
For a D7, generate a D8 with three odd/even rolls and keep 1-7, repeating all three rolls on an 8. For a D11, generate a D16 with four rolls and keep 1-11, repeating all four on a 12 to 16.
Every accepted number began as one equally likely odd/even sequence, so rejecting the unused ones does not favour any result you keep. This route is not always the quickest, which is why the D10, D12, D20 and D100 methods use the structure of those numbers instead.
Why 2D6 Is Not the Same as a D12
A D12 has twelve equally likely results, each with a probability of one in twelve. Rolling 2D6 means rolling two D6s and adding them, which only produces 2 to 12. Of the 36 ordered pairs, one makes a 2, six make a 7 and one makes a 12, so the middle is far more common than the ends. It is a triangular distribution, not a flat one.
If the rule says D12, use a flat D12 conversion. If it says 2D6, roll two D6s and add them.
Do These Methods Change the Odds?
No, provided the D6 is fair, the rolls are independent and you follow the mapping exactly.
In the methods without rejection, every final result receives the same number of D6 combinations. Each D3 result covers two faces of the six. Each D8 result covers 27 of the 216 possible three-roll sequences.
In the methods with rejection, the six is not reassigned to another number. It is discarded, leaving 1-5 equally likely once a valid result is obtained.
These are mathematically equivalent ways to generate a result, but that does not automatically make them an approved replacement in every game or event. In a casual game, agree the conversion before rolling. In organised play, follow the event pack and ask the organiser if a required die is missing. Mathematical equivalence does not automatically override an event’s dice policy.
Do You Need the Actual Dice?
Not for an occasional roll. Every conversion in this guide can produce the correct distribution when followed properly. Dedicated dice are faster to read and reduce the chance of forgetting which D6 had which job.
The longer methods wear thin. A D20 needs at least three ordered rolls and a D100 at least four, so they are worth converting when a die is missing and worth owning when the roll comes up often. The advantage is convenience, not a different probability.
Our Special and Extra Dice currently include dedicated D3 and scatter dice. For the D6s used in the conversions above, our Tabletop RPG Dice collection includes engraved, hand-painted designs for character and campaign themes.
The Short Version
A fair D6 can simulate every die in this guide. Use 1-2, 3-4 and 5-6 for a D3; ordered odd/even rolls for D2, D4, D8 and D16; a D6 plus a lower-or-upper-half roll for D12; and rejection for D5-based results such as D10 and D20. For any other Dn, generate the next power-of-two range and re-roll results that are too high. Just remember that adding 2D6 does not create a flat D12.