One-Rep Max Calculator
Enter a weight and how many reps you lifted it for — get your estimated one-rep max plus the training percentages to program your next block.
| % of 1RM | Weight | Typical use |
|---|---|---|
| 95% | heavy singles/doubles | |
| 90% | strength · 3–4 reps | |
| 85% | strength · 5–6 reps | |
| 80% | strength-hypertrophy · 7–8 | |
| 75% | hypertrophy · 8–10 | |
| 65% | volume · 12–15 |
Estimate uses the Epley and Brzycki formulas (averaged). Most accurate at 2–10 reps — actual maxes depend on technique, leverages, and training age. Warm up properly and use a spotter for true max attempts.
What is a one-rep max — and why estimate it?
Your one-rep max (1RM) is the heaviest weight you can lift for a single rep with good form. You don’t need to test it directly to train with it — estimating from a hard set of 2–10 reps is safer, nearly as accurate, and lets you program percentages for strength blocks. This calculator averages the two most-used formulas (Epley and Brzycki), then gives you the standard training percentages coaches program from.
Related: Sledgehammer pre-workout · Pure Power Creapure® creatine · all calculators
Frequently Asked Questions
How accurate are 1RM calculators?
Within a few percent for sets of 2–10 reps. Above 10–12 reps the estimate drifts, because high-rep sets test endurance as much as strength. Use a recent, hard, clean set for the best estimate.
Should beginners test their true 1RM?
Usually not. Estimating from a 5-rep set gives you everything you need to program, without the injury risk of a max attempt before your technique is solid.
What supplements actually help strength?
The best-supported one is creatine monohydrate — 3–5 g daily is one of the most-studied performance supplements in sports science. Caffeine pre-workout also has strong evidence for acute strength and power output.