How accurate is this One Rep Max Calculator?

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 Calculator is completely free to use. No registration or payment required.

Can I use this calculator on mobile?

Yes, our calculator is fully responsive and works on all devices including smartphones, tablets, and desktop computers.

One Rep Max Calculator

Calculate your one-rep max (1RM) for any lift based on submaximal weights

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.

One Rep Max

Estimate max strength safely.

One Rep Max Calculator

Your Lift

Results by Formula

Percentage of 1RM Chart

Training Zone Recommendations

Strength (1-5 reps)

Hypertrophy (6-12 reps)

Endurance (12+ reps)

One Rep Max