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3 rep max calculator
Enter a recent set, the weight, the reps and how many more you could have done. The calculator estimates your 3-rep max, the heaviest weight you could lift for three, and the load for heavy triples left 1, 2 or 3 reps short of failure.
Example result
152.5kg
163.5kg
From 140 kg × 5 with 1 in reserve, which counts as 6 reps to failure.
| Set | Load | % of 1RM |
|---|---|---|
| 3 reps to failure | 152.5 kg | 94% |
| 3 reps, 1 in reserve | 147.5 kg | 91% |
| 3 reps, 2 in reserve | 145 kg | 88% |
| 3 reps, 3 in reserve | 140 kg | 86% |
3 rep max examples
Four lifters planning heavy triples from the sets they already have.
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Example 1
Turning a 5RM test into triples
A lifter who benched 275 lb for 5 to failure and wants heavy triples for the next block.
- Weight lifted
- 275 lb
- Reps completed
- 5
- Reps in reserve
- 0
- Estimated 3-rep max290 lb
- Estimated 1RM312 lb
The 3RM comes out at 290 lb. Triples at 2 in reserve start at 275 lb, the same bar as the test, and the block builds from there.
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Example 2
A powerlifter's easy triple
A competitive lifter who squatted 180 kg for 3 with 2 left in a heavy session, eight weeks out from a meet.
- Weight lifted
- 180 kg
- Reps completed
- 3
- Reps in reserve
- 2
- Estimated 3-rep max192.5 kg
- Estimated 1RM204 kg
The triple at 2 in reserve is the set he just did, so the estimate agrees with the bar. Next week's heavy triple at 1 in reserve is 185 kg, 5 kg up.
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Example 3
A woman's first heavy squats
An intermediate lifter coming off a hypertrophy block: 60 kg for 6 with 2 left.
- Weight lifted
- 60 kg
- Reps completed
- 6
- Reps in reserve
- 2
- Estimated 3-rep max70 kg
- Estimated 1RM74 kg
Her 3RM estimate is 70 kg, but triples are new to her. Start at 3 in reserve, 62.5 kg, and move to 2 in reserve once the bar speed stays even across all three reps.
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Example 4
From a set of 8 to failure
A lifter who pulled 315 lb for 8 to failure on a high-rep day and wants a heavy deadlift triple.
- Weight lifted
- 315 lb
- Reps completed
- 8
- Reps in reserve
- 0
- Estimated 3-rep max365 lb
- Estimated 1RM389 lb
Eight reps is a long way from three, so treat the 365 lb estimate as an upper bound. A first heavy triple at 2 in reserve, 345 lb, tests the estimate without betting on it.
Why train heavy triples
A triple is close to your max without being a max attempt. It practices handling near-maximal loads, which is why strength and powerlifting programs use heavy triples and 3RM tests instead of frequent one-rep maxes.
It's also a better input for estimating your 1RM than a long set: the formula has less distance to cover. If you want the 1RM itself, run your triple through the one-rep max calculator.
A 3RM is about 94% of your max
By the formula this calculator uses, a 3RM is about 94% of your 1RM. Other calculators land a point or two lower; the difference is the formula, not you.
Programs that prescribe triples by percentage are usually asking for something lighter than a 3RM, often with a rep or two in reserve. The table under the result gives those loads directly, so you don't need the percentage at all.
How the 3RM is 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. The 3RM is that 1RM divided by the same factor for 3 reps, and each row of the table adds the reps in reserve to the 3.
Loads round to 2.5 kg or 5 lb. Inputs past about 10 reps to failure are flagged as rough.
1RM = weight × (1 + (reps + RIR − 1) ÷ 30)
3RM = 1RM ÷ (1 + (3 − 1) ÷ 30)
140 × (1 + (5 + 1 − 1) ÷ 30) = 163.33, shown as 163.5 kg
3RM = 163.33 ÷ (1 + 2 ÷ 30) = 153.1, shown as 152.5 kgMake it fit you
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Pick the right input
A set of 2 to 6 reps near failure predicts a 3RM best. From a set of 10 or more, treat the number as a ceiling and work up to it.
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Program at 1 or 2 in reserve
Heavy triples at 1 or 2 in reserve build strength without the recovery cost of a true 3RM. Save the to-failure row for a test day.
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Test a 3RM, then re-run it
If you test a real 3RM, enter it as 3 reps at RIR 0. The next block's triples then start from a measured number.
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Warm up in steps
Work up to a heavy triple in four or five jumps. The warm-up calculator sets them from your working weight, and the plate calculator loads them.
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Use fractional plates near the top
Near-max loads progress slowly. With 1.25 kg or 2.5 lb plates, smaller jumps let you add load to your triples more often.
Questions
What is a 3 rep max?
The heaviest weight you can lift for three clean reps, with nothing left. It's about 94% of a 1RM by the formula used here.
How do I convert a 5RM to a 3RM?
Enter the 5-rep set at RIR 0. The calculator estimates the 1RM from it and steps back to three reps; a 275 lb 5RM gives a 290 lb 3RM.
Is testing a 3RM safer than a 1RM?
It's lighter: about 94% of your max by this formula. You also get a good 1RM estimate from it without attempting one.
What weight should I use for heavy triples?
The row for the reserve your program asks for, usually 1 or 2 reps left. For percentage-based programs such as 5/3/1, use their own calculator.
How often should I retest my 3RM?
There's no need to test on a schedule. Re-run the calculator from your hardest recent set at the end of each block, and test only when a meet or a program calls for it.
Related calculators and templates
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Rep max calculator
Every rep max from 1 to 12 from the same set.
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One-rep max calculator
Your 1RM and 5RM, with the RIR chart.
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5/3/1 calculator
Training-max loads for a 5/3/1 cycle.
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RPE calculator
Loads for triples prescribed at an RPE.
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Top set and back-off sets
How to run a heavy triple and the volume after it.
Sources
Let your triples set the next session
Log load, reps and RIR on every heavy set and RIRLift keeps your estimated max current, then sets your next session's weights from what you actually lifted.
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