Loading...
Loading...
Loading tool...
Estimate your 1RM from submaximal lifts
Estimated One Rep Max
260lbs
Average of 5 formulas
Epley (1985): weight x (1 + reps/30)
+3
Brzycki (1993): weight x 36 / (37 - reps)
-7
Lombardi: weight x reps^0.1
+4
Mayhew et al.: regression-based
+8
O'Conner et al.: weight x (1 + reps x 0.025)
-7
Estimates are most accurate for 1-10 reps. Accuracy decreases with higher rep counts. Always use a spotter for heavy lifts.
⚠️ Health Disclaimer
This calculator provides estimates for informational purposes only. Results should not replace professional medical advice. Consult a healthcare provider before making changes to your diet or exercise routine.
As an affiliate, we may earn from qualifying purchases. Disclosure
Track your PRs and progressive overload with a workout journal. The old-school tool serious lifters swear by.
A one rep max (1RM) is the maximum weight you can lift for a single repetition with proper form. It is the standard measure of maximal strength and is used to program training percentages for strength and hypertrophy programs.
The Epley and Brzycki formulas are considered the most reliable for reps under 10. Epley tends to be slightly higher, Brzycki slightly lower. Both are within 5% of actual 1RM for most lifters. Accuracy decreases with higher rep counts (10+).
Testing a true 1RM carries higher injury risk than submaximal lifting. Use a spotter, proper warm-up, and good form. For most people, estimating 1RM from a 3-5 rep set is safer and nearly as accurate. Save true 1RM testing for competition preparation.
Common training zones: 50-65% for warm-ups and endurance, 65-75% for hypertrophy (muscle size), 75-85% for strength, 85-95% for peaking and max strength, 95-100% for competition. Programs like 5/3/1 and Starting Strength use 1RM percentages for programming.
One Rep Max Calculator is part of BriskTool's collection of free online tools. All processing runs entirely in your browser for maximum privacy and speed.