One-rep max calculator
To estimate your one-rep max, take a hard set of 1–10 reps and use the Epley formula: weight × (1 + reps ÷ 30). 100 kg for 5 reps estimates about 116.7 kg. This calculator uses the same function VALDA runs on every set you log.
Estimated one-rep max
Based on 5 reps. Epley is most reliable up to 10 reps.
| % of e1RM | Weight | Estimated reps |
|---|---|---|
| 100% | 116.7 kg | 1 |
| 95% | 110.8 kg | 1 |
| 90% | 105 kg | 3 |
| 85% | 99.2 kg | 5 |
| 80% | 93.3 kg | 7 |
| 75% | 87.5 kg | 10 |
| 70% | 81.7 kg | 12 |
| 65% | 75.8 kg | 16 |
| 60% | 70 kg | 20 |
The estimated reps column is the same formula run backwards. It's a guide to what a weight usually allows, not a target.
How VALDA calculates e1RM
The formula. VALDA uses Epley: estimated one-rep max = weight × (1 + reps ÷ 30). It's a straight line, so it works the same in kilograms and pounds.
Ten reps and under. Past about 10 reps, Epley overestimates, and light high-rep sets (warm-ups, empty-bar work) would produce inflated numbers. So a set above 10 reps gives no e1RM. It still counts towards your volume.
A single is a single. One rep at a weight is taken as a one-rep max of that weight.
Records. Each time you log a weighted set of 10 reps or fewer, VALDA works out its e1RM. If it beats your best for that exercise, it becomes your new estimated-1RM record.
One-rep max questions
How do I estimate my one-rep max?
Take a hard set of 1 to 10 reps and put the weight and reps into the Epley formula: weight × (1 + reps ÷ 30). 100 kg for 5 reps gives an estimate of about 116.7 kg.
Why does the calculator stop at 10 reps?
Rep-max formulas get less reliable as reps climb, and Epley drifts past about 10 reps. VALDA doesn't estimate a one-rep max from sets above 10 reps, so the calculator doesn't either.
Is an estimated one-rep max the same as a tested one?
No. It's an estimate of what you could likely lift once, based on a heavier set. A tested single on the day can come out higher or lower.
Does it work in pounds?
Yes. Switch to lb and enter the weight in pounds. Epley is a straight multiplication, so the estimate comes out in whichever unit you put in.
Which formula does VALDA use?
Epley, the same formula as this calculator. When you log a set of 10 reps or fewer, VALDA works out the e1RM and keeps your best as a record for that exercise.
Stop doing the maths
VALDA works out the e1RM of every set of 10 reps or fewer that you log, uses it to set your working weights when a programme calls for a percentage, and shows the plates to load on each side. Set a record and VALDA marks the moment, with a card to share. With VALDA Pro, your best is kept as a record for every exercise.
No account needed for this calculator. Nothing you type here is saved.