One Rep Max Calculator (1RM)
Estimate your one rep max from a set you've already done, plus a full percentage table for programming your next block.
Estimated 1 rep max
- Epley
- 263
- Brzycki
- 253
- Lombardi
- 264
- In kg
- 118
| % of 1RM | Weight | Typical reps |
|---|---|---|
| 100% | 260 lb | 1 |
| 95% | 247 lb | 2 |
| 90% | 234 lb | 4 |
| 85% | 221 lb | 6 |
| 80% | 208 lb | 8 |
| 75% | 195 lb | 10 |
| 70% | 182 lb | 12 |
| 65% | 169 lb | 16 |
| 60% | 156 lb | 20 |
Worked examples
How 1RM is calculated
A one rep max (1RM) is the heaviest weight you can lift for a single repetition with good form. You don't have to actually attempt one to know it. Three classic formulas estimate it accurately from any sub-maximal set up to about 8 reps:
- Epley:
1RM = weight × (1 + reps / 30) - Brzycki:
1RM = weight × 36 / (37 − reps) - Lombardi:
1RM = weight × reps^0.1
This calculator averages all three for a stable estimate, and gives you a full percentage chart so you can program the next training block directly from the number.
How to use your 1RM
The estimated 1RM is mostly useful as a programming anchor. Most strength programs prescribe work as a percentage of 1RM, for example, "5 × 5 at 80%" or "work up to a heavy single at 92%". The percentage chart on this page does that math for you.
Typical rep ranges by intensity:
- 95-100%: 1-2 reps (peak strength)
- 85-90%: 3-5 reps (strength)
- 75-80%: 6-8 reps (strength + hypertrophy)
- 65-70%: 10-12 reps (hypertrophy)
- 50-60%: 15+ reps (endurance)
Worked examples
Example 1. Bench 225 lb × 5 reps. Average estimate: ~262 lb. Programming: 5 × 5 at 80% ≈ 210 lb.
Example 2. Squat 100 kg × 8 reps. Average estimate: ~127 kg. Programming: 4 × 6 at 75% ≈ 95 kg.
Example 3. Deadlift 405 lb × 3 reps. Average estimate: ~441 lb. Programming: heavy single at 92% ≈ 405 lb (so the test set is itself near-max).
Common mistakes
- Using a set with multiple reps in reserve. The estimate assumes you went near failure.
- Plugging in 15+ reps. Estimates degrade badly above 8-10 reps.
- Re-testing every week. 1RM moves slowly. Retest every 6-12 weeks at most.
- Using touch-and-go reps on deadlift to estimate competition max. Different stimulus, different number.
- Ignoring form breakdown. A "1RM" with a bent back is not a 1RM, it's a near-miss.
FAQ
Should I actually test my 1RM in the gym?+
Rarely. Estimated maxes from a 3-8 rep set are nearly as accurate, far safer, and don't require a full warm-up build-up. Test in person only if you compete or genuinely need the number.
Which formula is most accurate?+
All three (Epley, Brzycki, Lombardi) are within 2-3% of each other up to about 8 reps. Above 8 reps, accuracy drops fast, we cap input at 12.
Why does the estimate look low compared to my best ever?+
Estimates assume the set was taken close to failure. If you stopped with reps in reserve, the calculator underestimates. Take the set to RPE 9-10 for the best estimate.
How do I use the percentage chart?+
Pick the rep range you want to train in and use the matching percentage. E.g., to do sets of 5, work at around 85% of estimated 1RM.
Can I use this for any lift?+
Works best for compound barbell lifts (squat, bench, deadlift, OHP). Less reliable for isolation movements where form breaks down quickly under load.
What if my reps were really fast?+
Fast reps with reserve in the tank → use a higher estimate. The calculator assumes RPE 8-9. Velocity-based training tools do this more precisely.
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