Free tool
1RM calculator
Enter the reps and weight of a set you have done to estimate your one-rep max, and the weight you could lift for other rep counts. In kilograms or pounds.
1RM calculator
Estimated one-rep max
76kg
From 60 kg × 8 reps, with weight × (1 + reps ÷ 30).
GymTribe works this out for every set you log.
Weight for other rep counts
| 1 rep | 100% | 76 kg |
|---|---|---|
| 3 reps | 91% | 69 kg |
| 5 reps | 86% | 65 kg |
| 8 reps (your set) | 79% | 60 kg |
| 10 reps | 75% | 57 kg |
| 12 reps | 71% | 54.5 kg |
How the estimate works
Your one-rep max (1RM) is the most weight you could lift for a single rep. Testing it directly is hard, so this calculator estimates it from a set you have already done, using the Epley formula: weight × (1 + reps ÷ 30).
A set of 8 reps at 60 kg gives an estimate of 76 kg. GymTribe uses the same formula for the estimated 1RM it charts on every exercise.
When it is less precise
The estimate works best for sets of about 2 to 10 reps taken close to failure. Sets of more than 10 reps, or sets you stopped well short of failure, give a rougher number.
Treat it as an estimate, not a tested max, and look at how it moves over weeks rather than at any single result.
Using the breakdown
Each row is the weight the formula predicts you could lift for that many reps. Use it to pick a starting weight for a set of 5 or a set of 10, then adjust by how the set feels.
If you try a true single, do it with a spotter or safety bars.
Want to see how your estimated 1RM, volume and personal records change over time? Read how to track strength progress, or see the muscles worked and technique for the squat, bench press and deadlift.