Enter a recent working set — any weight and rep count from 1 to 15 — and get an estimated one-rep max from four independent formulas: Brzycki, Epley, Lander, and O'Conner. The calculator also shows the average and a full percentage table so you can set training loads without guessing.
Enter a recent lift — weight and reps — to get an estimated one-rep max from four different formulas, plus the average. Most accurate for sets of 1–10 reps with good technique.
256.2 lb
Average (Brzycki, Epley, Lander, O'Conner)
Individual formula estimates
Brzycki
253.1 lb
Epley
262.5 lb
Lander
255.8 lb
O'Conner
253.1 lb
No single formula wins across all rep ranges. Brzycki tends to be more conservative at higher reps; Epley is commonly the most generous. The average of all four is generally more reliable than any single estimate, especially for sets of 3–8 reps.
Above 10 reps, muscular endurance and conditioning become a larger factor in how many reps you can complete. This makes the extrapolation to a single-rep max less reliable. Sets of 3–6 reps with solid technique give the most accurate estimates.
Use the table to set training loads as percentages of your estimated 1RM. For example, 80% is a common hypertrophy range for sets of 6–10. Check the RPE calculator if you want to account for daily variation in fatigue and readiness.
A 1RM estimate is most useful when you know how to apply it — which percentages to use, when to push, and when to hold back.