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One Rep Max Calculator

Calculate your estimated one rep max (1RM) using four validated formulas. Includes rep-max table, strength standards relative to body weight, and formula comparison cards.

Health

Weight Lifted

Reps Performed

Enter reps you completed with this weight (1-30).

Body Weight (optional — for strength standards)

Gender:

Understanding One Rep Max

Your one rep max (1RM) is the maximum weight you can lift for a single repetition with proper form. It is the gold standard for measuring strength and is used to set training loads for strength programs.

Training zones based on 1RM:

Strength: 85-100% of 1RM (1-5 reps)
Hypertrophy: 65-85% of 1RM (6-15 reps)
Endurance: 40-65% of 1RM (15+ reps)
Power: 50-70% of 1RM (explosive reps)

Safety note: Attempting a true 1RM requires a spotter and proper warm-up. Use estimated 1RMs from submaximal lifts for day-to-day training.

The Formulas

Epley

Most widely used, accurate for 1-10 reps.

Brzycki

Preferred for higher rep ranges (up to 15).

Lombardi

Better for explosive lifts like power cleans.

Lander

Accurate for 1-6 rep range.

Frequently Asked Questions

Which formula is most accurate?▾

The Epley formula is the most widely validated for the 1-10 rep range. Brzycki performs better for higher rep ranges (10-15). Taking the average across all four formulas gives the most reliable estimate for most lifters.

How often should I test my 1RM?▾

Most programs recommend testing every 4-12 weeks. Beginners should use estimated 1RMs from submaximal lifts rather than attempting true max lifts. Intermediate and advanced lifters can test more specifically for competition needs.

What is a good 1RM for my body weight?▾

Strength relative to body weight is a better measure than absolute numbers. A 1.5x body weight bench press or 2x body weight squat is considered intermediate for men. The strength standard chart in the calculator shows where you rank by lift and gender.

Can I use 1RM for all lifts?▾

Yes, but the formula accuracy varies by lift. The formulas work best for compound lifts (bench press, squat, deadlift) because they involve multiple muscle groups. Isolation exercises may not follow the same strength-curve pattern.

Should I train at my 1RM?▾

Training at your 1RM is not recommended for regular workouts due to high injury risk and CNS fatigue. Use percentages of your estimated 1RM (e.g., 70-85% for most training) and only attempt true 1RM lifts when properly prepared with a spotter.

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How to Use This Tool

Enter the weight you lifted and the number of reps you completed (1-30 reps).
Toggle between kg and lbs using the unit button.
Optionally enter your body weight and gender for strength standards comparison.
View your estimated 1RM as the average across all four formulas.
Compare results from Epley, Brzycki, Lombardi, and Lander formulas on the comparison cards.
Check the rep-max table to see estimated weights for any rep target from 1 to 20.

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