How accurate is this One Rep Max?

Our calculator uses scientifically validated formulas and provides results based on peer-reviewed research. Results should be used as a general guide and not as medical advice.

Is this tool free to use?

Yes, this One Rep Max is completely free to use. No registration or payment required.

Can I use this calculator on mobile?

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One Rep Max

Fitness & Exercise

One Rep Max helps you Plan training, recovery, and performance targets from simple fitness inputs.

One Rep Max Calculator

Estimate your maximum strength using multiple proven formulas

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Estimated One Rep Max

Results by Formula

Formula	Estimated 1RM	Accuracy
Epley	--	Most Popular
Brzycki	--	Best for 1-10 reps
Lander	--	General purpose
Lombardi	--	Higher rep ranges
Mayhew	--	Football players

Percentage of 1RM Chart

Training Zone Recommendations

Strength (1-5 reps)

Maximum strength & neural adaptation

85-100%

Hypertrophy (6-12 reps)

Muscle growth & size

65-85%

Endurance (12+ reps)

Muscular endurance & conditioning

50-65%

Safety Note: These are estimates. Always use a spotter when attempting maximal lifts. Start with a conservative weight and work up gradually. Stop if you feel any pain or discomfort.

About the One Rep Max

This tool turns common health inputs into a clear, educational result you can use to understand your current patterns and prepare better questions for a qualified healthcare professional.

Results are informational and are not a diagnosis, prescription, or substitute for medical care.

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