Two formulas do almost all the work
Both take the weight you lifted and the reps you managed, then extrapolate to a single max. Epley is the common default; Brzycki is slightly more conservative and holds up better at higher reps.
Example: 100 kg for 5 reps gives 117 kg by Epley and about 113 kg by Brzycki. They only diverge as reps climb, which is why estimates from low-rep sets are the ones to trust.
Percent of 1RM by training goal
| % of 1RM | Rep range | What it trains |
|---|---|---|
| 95–100% | 1–2 | Maximal / testing |
| 85–95% | 3–5 | Maximal strength |
| 70–85% | 5–8 | Strength & size |
| 60–70% | 8–12 | Hypertrophy |
| 50–60% | 12–15 | Power / speed, deloads |
If your estimated max is 120 kg, a 75% working set is 90 kg. Round to the nearest plate you actually have.
Accuracy depends on the rep count
- Low reps win. A 3 to 8 rep set estimates within about 5 to 10%. Past 15 reps the error can reach 15 to 25%, so lift heavier for fewer reps if you want a real number.
- It is a model, not your body. Formulas ignore sex, age, and training experience. Two lifters with the same bench max can have very different deadlifts, so estimate each lift separately.
- Compound lifts are cleaner. Squat, bench and deadlift track the formulas well. Isolation moves like curls are noisier because stabilizers and technique matter more.
Common questions
Which 1RM formula is most accurate?
None is best for everything. Epley and Brzycki are the most widely used and agree closely in the 2 to 10 rep range. Epley tends to run high above 10 reps; Brzycki stays more conservative there. Estimates are most reliable at low reps, so a 3 to 5 rep set beats a 15 rep set.
How many reps should I use for an accurate estimate?
Pick a weight you can lift for about 3 to 8 hard reps. That range keeps the error near 5 to 10%. Above 10 to 15 reps the estimate drifts, and past 20 reps it is not worth using.
How do I use the percentage table to train?
Multiply your estimated 1RM by the percentage for your goal. Strength work sits around 85 to 95% for low reps, hypertrophy around 70 to 80% for moderate reps, and power or speed work lower. Never max-test every session; re-estimate every 8 to 12 weeks instead.
