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Rep max calculator
Enter any recent set, the weight, the reps and how many more you could have done. The calculator turns it into your full rep max ladder, from 1RM to 12RM, with a second column for the same rep counts stopped 2 reps short of failure, the way most programs write working sets.
Example result
116.5kg
From 100 kg × 5 with 1 in reserve, which counts as 6 reps to failure.
| Rep max | To failure | With 2 in reserve | % of 1RM |
|---|---|---|---|
| 1RM | 116.5 kg | 110 kg | 100% |
| 2RM | 112.5 kg | 105 kg | 97% |
| 3RM | 110 kg | 102.5 kg | 94% |
| 4RM | 105 kg | 100 kg | 91% |
| 5RM | 102.5 kg | 97.5 kg | 88% |
| 6RM | 100 kg | 95 kg | 86% |
| 7RM | 97.5 kg | 92.5 kg | 83% |
| 8RM | 95 kg | 90 kg | 81% |
| 9RM | 92.5 kg | 87.5 kg | 79% |
| 10RM | 90 kg | 85 kg | 77% |
| 12RM | 85 kg | 82.5 kg | 73% |
Rep max examples
Four lifters, four lifts, one ladder each. Open any example to see its full table.
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Example 1
Planning a block from a set of 8
An intermediate lifter who benched 185 lb for 8 with 2 left at the end of a hypertrophy block.
- Weight lifted
- 185 lb
- Reps completed
- 8
- Reps in reserve
- 2
- Estimated 1RM241 lb
For a strength block of fives, the 5RM row says 210 lb to failure and 200 lb with 2 in reserve. Start the working sets at 200 lb, not at a percentage of a max he never tested.
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Example 2
A powerlifter's heavy double
A competitive lifter who squatted 315 lb for 2 with 1 rep left in a heavy session.
- Weight lifted
- 315 lb
- Reps completed
- 2
- Reps in reserve
- 1
- Estimated 1RM336 lb
Low-rep sets predict the top of the ladder best. The 3RM row comes out at 315 lb to failure, so the double was a near-max triple, and triples for the next block start a step lighter.
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Example 3
A beginner's squat at 3 in reserve
Two months in, 60 kg for 6 reps that still moved fast, about 3 more in the tank.
- Weight lifted
- 60 kg
- Reps completed
- 6
- Reps in reserve
- 3
- Estimated 1RM76 kg
Counting the reserve makes this a 9-rep effort, so the 8RM row with 2 in reserve, 57.5 kg, is a solid working weight for sets of 8. Add 2.5 kg when every set feels easier than that.
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Example 4
Ten reps on a light day
A lifter returning from a break who did 40 kg for 10 with 1 left.
- Weight lifted
- 40 kg
- Reps completed
- 10
- Reps in reserve
- 1
- Estimated 1RM~53.5 kg
Eleven reps to failure is past where rep max estimates hold up, so the top of this ladder is rough. Use the 10RM and 12RM rows now, and re-test with a heavier set of 5 in a couple of weeks.
What a rep max is
A rep max is the heaviest weight you can lift for a given number of clean reps. Your 1RM is one rep; your 8RM is the most you could do for exactly 8. Every rep max sits on the same curve, so one hard set gives a good estimate of all of them.
If you only need one rung, there are pages for each: the 3 rep max calculator for heavy triples, the 10 rep max calculator for sets of 10, and the one-rep max calculator for the 1RM itself and your 5RM.
Why the table has a reps-in-reserve column
A rep max is a set to failure. Most programs don't train there: they ask for sets of 5 or 8 with a rep or two left, which is lighter than the rep max. The second column gives that load, for each rep count with 2 reps in reserve.
The input works the same way. A set of 6 with 3 left is a 9-rep effort, not a 6RM, and treating it as one would put every number on the ladder too low.
How the rep maxes are calculated
Your set becomes a 1RM with Epley's formula, the same one the RIRLift app uses, with the reps you had left added to the reps you did. Each rep max is then the 1RM divided by the same factor for that rep count.
Rep maxes round to 2.5 kg or 5 lb so you can load them. Estimates hold best from sets of 3 to 8 reps and drift past about 10 reps to failure.
1RM = weight × (1 + (reps + RIR − 1) ÷ 30)
NRM = 1RM ÷ (1 + (N − 1) ÷ 30)
100 × (1 + (5 + 1 − 1) ÷ 30) = 116.67, shown as 116.5 kg
5RM = 116.67 ÷ (1 + 4 ÷ 30) = 102.9, shown as 102.5 kgMake it fit you
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Use your hardest recent set
The closer a set is to failure, and the closer it is to 3 to 8 reps, the tighter the ladder. A warm-up set tells the calculator very little.
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One lift per ladder
Rep maxes don't transfer between lifts. Run a squat set for squat numbers and a bench set for bench numbers.
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Trust the rows near your set
The further a row is from the reps you entered, the more it relies on the formula. A set of 8 predicts your 6RM to 10RM better than your 1RM.
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Round to your equipment
Barbell loads round to 2.5 kg or 5 lb. For dumbbells or a machine stack, round each row to the nearest weight you have.
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Turn rows into sessions
Pick a row, then set the reps in reserve you want. The sets and reps calculator helps choose the rep range for your goal.
Questions
How do I find my rep max without testing it?
Enter a hard set of 3 to 8 reps and the reps you had left. The calculator estimates every rep max from it, so you never have to grind out a max set.
What percentage of 1RM is each rep max?
By this formula, about 94% for a 3RM, 88% for a 5RM, 81% for an 8RM and 77% for a 10RM. The full list is in the one-rep max chart.
How accurate are rep max calculators?
Close from a hard set of 3 to 8 reps, looser from high-rep sets. In one study, 5-rep sets predicted the 1RM better than 10- or 20-rep sets.
Why are my rep maxes lower than another calculator's?
If you entered reps in reserve, they shouldn't be. If another calculator gives more for the same set at RIR 0, it likely uses a different formula; Epley and Brzycki agree closely up to about 10 reps.
What does "with 2 in reserve" mean in the table?
The load for that many reps with 2 more left in the tank. It's how most working sets are prescribed, and why it sits below the rep max. The RIR calculator shows how reserve maps to effort.
Related calculators and templates
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One-rep max calculator
Your 1RM and 5RM from one set, with the RIR chart.
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3 rep max calculator
The heavy triple, at failure and with reps in reserve.
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10 rep max calculator
Loads for sets of 10.
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1 rep max chart
Percentages of your max for every rep count.
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Best rep range for muscle growth
Which rungs of the ladder to train for size.
Sources
Keep the whole ladder current
Log load, reps and RIR on every set and RIRLift keeps your estimated max for each lift up to date, then picks the next session's weights from what you did.
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