1RM calculator.

How this calculator works

Your one-rep max is the heaviest weight you could lift for a single clean rep. Testing it for real is risky and tiring, so coaches estimate it from a submax set instead. Log any working set of 1 to 15 reps above and the tool runs it through three published formulas, where w is the weight lifted and r is the reps performed.

Epley is the most common starting point and the headline number above. Brzycki tends to read a touch lower at higher rep counts, Lombardi a touch flatter. All three agree closely between 1 and 10 reps. Past that the estimate gets soft, which is why this calculator stops at 15.

Using the percentage ladder

Training blocks are usually written as percentages of 1RM. The ladder converts your estimate into working weights: roughly 95% for doubles, 80% for sets of eight, and 65 to 60% for higher-rep work. Treat them as starting points and let bar speed and RPE confirm the load on the day.

Planning the diet side of a block too? Pair this with the TDEE calculator and the macro calculator.