Estimate your 1RM strength using Epley, Brzycki, and Lombardi formulas
Tracking health metrics shouldn't require doctor visits for every quick estimate. One Rep Max Calculator lets you estimate your 1rm strength using epley, brzycki, and lombardi formulas instantly with science-backed formulas. All calculations run in your browser, and no personal health data is stored or transmitted anywhere.
Your 1RM is the maximum weight you can lift for one complete repetition with proper form. It's the gold standard for measuring absolute strength and is used to set training weights as percentages. Since true 1RM testing carries injury risk, these formulas let you estimate it safely from a submaximal set (typically 3–10 reps).
Epley and Brzycki are the most widely used. Epley tends to slightly overestimate for higher rep ranges; Brzycki is slightly more conservative. Accuracy decreases as reps increase — for best results, use a set of 3–5 reps. Using the average of multiple formulas reduces individual formula bias.
Program your training weights as percentages of 1RM: 90–100% for max strength (1–3 reps), 80–90% for strength (3–5 reps), 70–80% for hypertrophy (6–12 reps), 60–70% for muscular endurance (12–20 reps). Recalculate your 1RM every 4–8 weeks as your strength improves to keep progressively overloading.