One-rep max calculator
Enter a set you've done and get your estimated one-rep max, plus the weights to use at common training percentages.
Estimated 1RM
212lb
| 95% | 201lb |
|---|---|
| 90% | 191lb |
| 85% | 180lb |
| 80% | 170lb |
| 75% | 159lb |
| 70% | 148lb |
| 60% | 127lb |
How your 1RM is estimated
The calculator averages two standard formulas. Epley: 1RM = weight × (1 + reps ÷ 30). Brzycki: 1RM = weight × 36 ÷ (37 − reps).
Use your hardest recent set, ideally between 3 and 8 reps. The percentage chart lets you plan sessions: roughly 85–95% for heavy strength work, 70–80% for classic hypertrophy sets, and 60% for technique or warm-ups.
Track your PRs automatically
Helthy logs every set and automatically detects new records for max weight, max reps and max volume on every exercise, so you always know when you've got stronger.
One-rep max questions
What is a one-rep max?
Your one-rep max (1RM) is the heaviest weight you can lift for a single rep with good form. Programs often prescribe weights as a percentage of it, such as 3 sets of 5 at 80%.
How accurate is a 1RM calculator?
Estimates are most accurate from heavy sets of about 3–8 reps taken close to failure. Above 10–12 reps the formulas drift, because muscular endurance varies a lot between people.
Which 1RM formula is best?
Epley and Brzycki are the most widely used and give very similar answers at low reps. This calculator averages the two.
Should I test my real one-rep max?
You don't need to. Testing a true max carries more risk and fatigue, and an estimate from a hard set of 3–5 is accurate enough to program from.
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