Estimate your one-rep max

The job

Programs prescribe loads as a percentage of your one-rep max, but attempting a true single is risky without a spotter. Estimating from a normal working set — the weight you lifted and the reps to failure — gives a usable number without the all-out attempt.

How to do it

Enter the weight and the reps you completed to failure, and choose kg or lb. The tool applies three established formulas — Epley, Brzycki, and Lombardi — and shows all three with their average, plus a percentage table for picking training loads.

• Use a set of 1–15 reps taken to failure; below about 10 reps the estimate is most reliable.
• A single rep needs no estimate — it already is your max.

Worked example

Lifting 60 kg for 8 reps gives roughly 75–80 kg depending on the formula — Epley says about 76, Brzycki about 78. The 80% row of the table then gives a sensible working weight around 60–62 kg for volume sets.

Limits

These are population-level formulas; technique, tempo, and fatigue change the answer. Accuracy drops past about 10 reps, and the estimate is for planning loads — not for testing under a heavy bar without a spotter.