One Rep Max Calculator

One Rep Max Calculator estimates the heaviest weight you could lift for a single repetition from a set of 1 to 20 reps. It shows the Epley, Brzycki and Lander estimates, their average, and a table of training loads from 95% down to 50% of that average, in kilograms or pounds.

Many strength programmes prescribe loads as a percentage of your one-rep max, but testing a true maximum is tiring and riskier. Estimating it from a heavy set lets you plan training loads without a maximal attempt.

1. Enter the weight you lifted and choose kg or lb.
2. Enter the number of clean repetitions you completed (1–20).
3. Press Estimate 1RM.
4. Compare the three formula estimates and their average.
5. Use the training-load table to plan sets, then copy or download the summary.

• Epley, Brzycki and Lander formulas plus their average
• Training-load table from 95% to 50% in 5% steps
• Kilograms or pounds
• Whole repetitions from 1 to 20, with a reliability warning above 10
• A single rep is treated as the 1RM itself
• Formulas and inputs included in the summary

• Use a set of about 3–8 reps taken close to failure for the best estimate.
• Count only reps completed with good technique.
• Re-estimate every few weeks as you get stronger.
• Round table loads to the plates and dumbbells you have available.