A one-repetition maximum (1RM) estimate converts a submaximal set into an approximate maximum lift. It helps lifters choose training percentages without attempting a true maximal repetition. This page reports a blended estimate plus two common formulas, which makes the uncertainty visible rather than presenting one equation as exact.
Use the weight completed with consistent form.
Use a challenging set of 1 to 12 repetitions; estimates become less reliable at higher repetitions.
Compare Epley and Brzycki estimates.
The 80% figure can guide programming but should be adjusted for fatigue and technique.
A completed single repetition is treated as the entered weight itself.
The result approximates maximal strength for that lift under similar conditions.
Do not attempt a maximal lift without appropriate experience, technique, equipment, and supervision.
Given: 100 kg for 5 repetitions.
Calculation: Epley = 100 × (1 + 5/30) = 116.67 kg. Brzycki = 100 × 36/(37−5) = 112.50 kg.
Result: Average estimate = 114.58 kg; 80% training load is about 91.67 kg.
Neither is universally best. Individual exercise selection, training history, and repetition speed can shift the relationship.
Prediction error generally grows as the set moves farther from a true maximum.
Yes. The formulas preserve the input unit, so the result is in pounds if the entered weight is pounds; the on-screen label is nominal.
No. Use only completed repetitions performed with acceptable technique.
Treat it as a planning estimate, not clearance to attempt a maximal lift. Use spotters and qualified coaching where appropriate.