One-Rep Max
Estimated one-rep max by Epley formula from weight and reps (kg).
How it works
1RM ≈ weight(kg) × (1 + reps ÷ 30) (Epley formula)
One-rep max (1RM) is the heaviest weight you can lift for a single rep. The Epley formula back-estimates it from a set of reps, so you need not test the true limit.
FAQ
Is Epley accurate?
Reliable within ~1–10 reps; error grows with more reps and is affected by technique and fatigue, so use it as a guide.
Worked example
Epley estimate: 1RM = weight × (1 + reps ÷ 30).
If you lift 80 kg for 5 reps: 80 × (1 + 5/30) ≈ 93.3 kg, so your estimated one-rep max is about 93 kg.
Notes and limitations
Accuracy is best in the 1–10 rep range and degrades as reps rise. Use the estimate to program loads, not as a reason to attempt a true max — build up gradually with a spotter.