One Rep Max Calculator
Estimate your 1 rep max from any submaximal set using three established formulas. Get a full training percentage table for programming your bench press, squat, deadlift, or any lift.
The weight you used for the set below
Most accurate between 1–10 reps. Above 10 reps, accuracy decreases.
Training Zones by 1RM Percentage
| % of 1RM | Rep Range | Training Goal | Examples |
|---|---|---|---|
| 95–100% | 1–2 | Maximum strength | Competition, testing |
| 85–95% | 2–3 | Near-maximal strength | Strength peaking |
| 80–85% | 3–5 | Strength development | 5×5, 3×3 programs |
| 70–80% | 5–8 | Strength-hypertrophy | 5/3/1, Wendler programs |
| 60–70% | 8–12 | Hypertrophy | Most bodybuilding work |
| 50–60% | 12–20 | Muscular endurance | Circuit training, speed work |
Frequently Asked Questions
How accurate is a one rep max calculator?
1RM calculators are estimates — accuracy varies with rep range and individual response. They are most accurate for 1–5 reps (±2–5% error). Accuracy decreases as reps increase: at 10 reps the error can be ±8–15%, and above 15 reps the formulas become unreliable. If you regularly train in the 3–6 rep range, calculated 1RM will closely match your actual max. For higher rep training, test a true 1RM with proper warm-up for accurate programming.
Which 1RM formula is most accurate?
No single formula is universally most accurate — different formulas are more accurate for different rep ranges and individuals. Epley tends to slightly overestimate at high reps; Brzycki is more accurate at low reps (1–5); Lander gives a conservative estimate. Using the average of all three (as this calculator does) typically reduces individual formula error. For best results, use the formula that historically matches your actual performance when you do test your 1RM.
How do I use my 1RM for programming?
1RM percentages guide training intensity. Common zones: 90–95% 1RM = maximal strength (1–3 reps), 80–85% = strength development (3–5 reps), 70–80% = strength-hypertrophy (5–8 reps), 60–70% = hypertrophy (8–12 reps), 50–60% = endurance/speed work (12+ reps). Programs like 5/3/1 (Wendler), Starting Strength, and NSCA guidelines are built around these percentages.
Should I ever test my actual 1RM?
Occasionally — but with caution. Testing a true 1RM requires thorough warm-up (progressively working up to near-max loads over 15–20 minutes), good technique, a spotter, and sufficient training experience. Beginners should not test true 1RM — calculated estimates from submaximal sets are safer and sufficiently accurate for programming. Intermediate and advanced lifters can test true 1RM every 6–12 weeks when peaking.
Can I use this for any lift?
Yes — the 1RM formulas apply to any barbell or machine exercise where you can perform a maximal lift safely. Most commonly used for bench press, squat, and deadlift. The formulas assume similar motor patterns and fatigue responses, so they work best for compound movements. Accuracy may be lower for isolation exercises (curls, lateral raises) where the rep-to-rep fatigue pattern differs.