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1RM Calculator
How much can you lift at most, without actually trying? Enter the weight and reps of your last heavy set and instantly see your estimated 1RM, plus the weight that belongs to each training zone.
Use a weight where you had almost no reps left (RPE 8-10) for a reliable estimate. Above 12 reps, the formula becomes less accurate.
Estimated 1 Rep Max
116.7
kgCalculated using the Epley formula
Saved in this browser only.
Training zones
01
Choose a heavy set
Take a set of 3 to 8 reps where you had almost nothing left. The closer to failure, the better the estimate.
02
Watch your technique
Only use sets with clean form. A sloppy set makes you look stronger than you are.
03
Measure per exercise
Your 1RM differs per exercise. Estimate it separately for squat, bench press, and deadlift.
How reliable is this estimate?
The Epley formula estimates your 1RM based on weight and reps, but it is an approximation — not an exact measurement. The closer you stay to 1-3 reps, the more accurate the estimate.
What is the Epley formula?
A widely used formula to estimate your one-rep max from a set of multiple reps: 1RM = weight × (1 + reps ÷ 30). It is not perfect, but it gives a useful estimate without you having to attempt a maximal lift.
Why does the estimate become less accurate with more reps?
Above 12 reps, endurance and technique play a bigger role than pure strength, so the formula predicts less well. For a reliable estimate, it is best to use a weight where you have almost nothing left after 3 to 8 reps.
Do I really need to test my 1RM to train?
No. An estimated 1RM from this calculator is enough to determine your training zones. Testing a true maximal lift is taxing on your body and increases injury risk, especially without experience or a spotter.
How often should I re-estimate my 1RM?
Every 4 to 8 weeks is enough, or whenever your working weights start to feel structurally easier than before.