Estimate your 1-rep max
Enter one honest set: the weight, the reps, and how close to failure you got. You'll get your estimated max (your e1RM) plus the right load for every rep range. It's an estimate, not a tested max, and it runs in your browser, so nothing leaves your device.
| Reps | % of max | Load (kg) | Use |
|---|---|---|---|
| 1 | 100% | 112.5 kg | Strength |
| 2 | 97% | 110 kg | Strength |
| 3 | 94% | 107.5 kg | Strength |
| 4 | 92% | 102.5 kg | Strength |
| 5 | 89% | 100 kg | Strength |
| 6 | 86% | 97.5 kg | Hypertrophy |
| 8 | 81% | 90 kg | Hypertrophy |
| 10 | 75% | 85 kg | Hypertrophy |
| 12 | 71% | 80 kg | Hypertrophy |
| 15 | 67% | 75 kg | Endurance |
| 20 | 60% | 67.5 kg | Endurance |
Use these loads as starting estimates. Formula agreement is not a confidence interval. Higher-rep sets and uncertain reps in reserve make predictions less useful. The 4+ option uses four reps in reserve, so more reps left would imply a higher max.
Use these ranges as practical guides, not hard rules. Their effects overlap: every rep range can build strength, muscle and endurance. The labels show what each range tends to emphasise, not what it is limited to.
Max strength
Heavy loads, low reps, long rests (3-5 min). Builds raw force. Leave a rep in the tank on most sets, since true singles are taxing.
Muscle & size
Moderate loads, 1-3 min rests, sets pushed close to failure (1-3 left). A practical range for repeated hard sets.
Endurance & work
Lighter loads and higher reps build local muscular endurance. Adjust rest to keep good technique. Useful for conditioning and accessories.
Your numbers stay on your device.
Your max is estimated from the set you enter. The maths joins Brzycki- and Epley-style curves at 10 reps. The lift-type adjustments are planning assumptions; individual capacity varies by lifter and exercise. How close to failure you went matters: a set with reps to spare points to a higher max than the same set to failure. Treat the loads as a starting point. Don't test a true max without a warm-up and a spotter, and if you're injured or new to lifting, get a coach first.
Want these numbers in a real plan?
Knowing your max is step one. A coach turns it into week-to-week loading that actually moves: choosing the rep ranges, managing fatigue, and adjusting to how you're lifting instead of a fixed chart.