1RM Calculator – Estimate Your One Rep Max
Enter a set you have already lifted and get your estimated one rep max from seven formulas, with percentages, rep maxes, a training max and warm-up sets. Instant, free, and nothing leaves your browser.
Your estimated 1RM
1RM · estimated
115.5kg
≈ 254.6 lb
Consensus of 7 of 7 formulas · 100 kg × 5 reps
Lowest 112.5Highest 119 kg
Estimates only. Not medical or coaching advice.
Formula comparison
Seven published formulas convert a submaximal set into a 1RM estimate. They disagree a little, and that is useful: the consensus is the average of the formulas you keep ticked. Use the arrow on any row to see the maths with your own numbers.
| Formula | Estimate | vs. avg (difference from the consensus) | Show calculation |
|---|---|---|---|
| 116.7 kg | +1.0% | ||
Your numbers: Linear and slightly generous at higher reps. The most widely used formula. | |||
| 112.5 kg | −2.6% | ||
Your numbers: Tends to be conservative at low reps and climbs fast beyond 10 reps. | |||
| 117.5 kg | +1.7% | ||
Your numbers: Power-law curve. Gives higher estimates than most formulas at 2–6 reps. | |||
| 112.5 kg | −2.6% | ||
Your numbers: Simple linear model, usually among the lowest estimates. | |||
| 116.6 kg | +0.9% | ||
Your numbers: Exponential model fitted to rep-max data; close to Epley at moderate reps. | |||
| 119 kg | +3.0% | ||
Your numbers: Developed from bench press data in trained athletes; usually on the higher side. | |||
| 113.7 kg | −1.5% | ||
Your numbers: Linear in the denominator; behaves much like Brzycki at low reps. | |||
| Consensus (average of ticked) | 115.5 kg | ±2.8% | |
The formulas agree within 5.6% for this set.
1RM percentage table
Working weights from 50% to 100% of your estimated max, with the reps you could typically manage at each load.
| % of 1RM | Weight | Reps | Typical use |
|---|---|---|---|
| 100% | 115 kg | ≈ 1 | Peaking / max attempts |
| 95% | 110 kg | ≈ 2 | Peaking / max attempts |
| 90% | 105 kg | ≈ 4 | Heavy strength work |
| 85% | 97.5 kg | ≈ 6 | Heavy strength work |
| 80% | 92.5 kg | ≈ 8 | Strength & power |
| 75% | 87.5 kg | ≈ 11 | Strength & power |
| 70% | 80 kg | ≈ 14 | Hypertrophy & volume |
| 65% | 75 kg | ≈ 16 | Hypertrophy & volume |
| 60% | 70 kg | ≈ 19 | Technique & speed |
| 55% | 62.5 kg | ≈ 22 | Technique & speed |
| 50% | 57.5 kg | ≈ 25 | Warm-up & recovery |
2RM–10RM estimates
The heaviest weight you could expect to lift for each rep count. Your own set is highlighted when it falls in this range.
| Rep max | Weight | % of 1RM |
|---|---|---|
| 1RM | 115 kg | 100% |
| 2RM | 110 kg | 94% |
| 3RM | 105 kg | 91% |
| 4RM | 102.5 kg | 89% |
| 5RMyour set | 100 kg | 87% |
| 6RM | 97.5 kg | 84% |
| 7RM | 95 kg | 82% |
| 8RM | 92.5 kg | 80% |
| 9RM | 90 kg | 78% |
| 10RM | 87.5 kg | 76% |
Training max
Many programmes (5/3/1 for example) base their percentages on a training max slightly below your true max, so every session leaves room to progress.
105 kg
90% of your estimated 1RM of 115.5 kg
- Base programme percentages on this number, not your true max.
- Re-test or re-calculate every 4–8 weeks and move it up when sets feel easy.
- A lower percentage (80–85%) suits beginners or high-volume blocks.
Warm-up sets
A simple ramp that builds to your target without tiring you out. Pick the top set you are warming up for.
| Set | Weight | Reps | % of 1RM |
|---|---|---|---|
| Empty bar | 20 kg | 10 | 17% |
| Warm-up 1 | 45 kg | 5 | 39% |
| Warm-up 2 | 70 kg | 3 | 61% |
| Warm-up 3 | 87.5 kg | 2 | 76% |
| Warm-up 4 | 100 kg | 1 | 87% |
| Max attempt | 115 kg | 1 | 100% |
Rest 1–2 minutes between warm-up sets and 3+ minutes before the top set.
How this 1RM calculator works
A one rep max (1RM) is the heaviest weight you can lift for a single clean repetition. Testing it directly is tiring and carries more risk than most sessions need, so this calculator estimates it from a lighter set you have already done. The closer that set is to a heavy 2–6 reps, the better the estimate.
- Enter your set. The weight and the number of reps you completed. If you stopped with reps left, add your RPE or reps in reserve and the calculator adds those reps back in.
- Seven formulas run at once. Epley, Brzycki, Lombardi, O'Conner, Wathan, Mayhew and Landers each give an estimate. Nothing is hidden: open any row to see the equation filled in with your numbers.
- The consensus is the average. Averaging smooths out the quirks of any single formula. Untick a formula to leave it out and the result updates instantly.
- Everything else follows from that number. Percentages, rep maxes, your training max and the warm-up ramp are all calculated from the consensus estimate.
Please note: 1RM formulas give estimates, not guarantees. Fatigue, technique, sleep and the lift itself all change what you can do on the day. This tool is for planning only and is not medical or coaching advice. Use spotters or safety arms when testing heavy weights.