One Rep Max
Calculate your one-rep max from submaximal lifts
These calculators provide general information only and are not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider.
How to use One Rep Max
- 1Choose the lift you want to estimate, such as bench press, squat or deadlift.
- 2Enter a weight and the number of clean reps you can do, ideally between 2 and 10.
- 3Read your estimated one-rep max and the training loads at each percentage.
How a one-rep max is estimated
Epley: 1RM = weight × (1 + reps ÷ 30)A one-rep max is the heaviest weight you can lift once with good form, and it anchors most strength programming. Testing it directly demands a long warm-up and carries injury risk, so in practice it is estimated from a set of multiple reps. The widely used Epley formula assumes each additional rep corresponds to roughly 3.33% less weight, which is one thirtieth.
Other formulas such as Brzycki, Lombardi and O'Conner agree closely between 1 and 10 reps, usually within 2% to 5%, but accuracy collapses beyond about 10 reps because endurance, lactate tolerance and conditioning start to dominate rather than pure strength. Base your estimate on a set of 2 to 10 reps. Remember too that the result is a programming reference, not a competition number: your true max on a given day depends heavily on fatigue, technique and how thoroughly you warmed up.
| Formula | Estimated 1RM | Note |
|---|---|---|
| Epley | ≈ 93.3 kg | Most common, good for 1–10 reps |
| Brzycki | ≈ 90.3 kg | Slightly conservative |
| Lombardi | ≈ 92.8 kg | Exponential relationship |
| O'Conner | ≈ 92.0 kg | More stable at higher reps |
Formula comparison (bench press 80 kg × 5)
Frequently asked questions
Can I just attempt the estimated max?
Not recommended, especially if you are relatively new to training. Estimates can sit 5% to 10% away from your true max, so going straight for the number carries real risk. A safer route is to test 90% of the estimate, confirm the technique holds, then add 2.5 to 5 kg per attempt until form breaks, always with a spotter or safety bars.
Why does the estimate get worse with more reps?
Because the limiting factor changes. Sets of 1 to 5 reps reflect maximal strength, but beyond roughly 10 to 12 reps, muscular endurance, lactate tolerance and conditioning take over, and those are not a linear extension of pure strength. Every formula therefore states a valid range, usually 2 to 10 reps, and results distort badly outside it.
How should I set training loads from a 1RM percentage?
A common structure is 85% to 100% for 1 to 5 reps for strength, 65% to 80% for 6 to 12 reps for hypertrophy, and 60% to 70% for 15 to 20 reps for endurance. Beginners do well starting at 60% to 70% while they groove technique, then raising intensity gradually. Exact percentages shift with training age and recovery capacity.
What is a normal ratio between lifts?
Individual variation is large, but rough benchmarks for trained lifters are a squat around 1.5 times bodyweight, a bench around 1.0 times and a deadlift around 1.75 to 2.0 times. Female lifters typically reach about 60% to 70% of the numbers of a male of the same bodyweight, largely because of differences in muscle distribution and hormones. Treat these as context, not targets.