One Rep Max Calculator

Estimate your 1RM and percentage-based lifting targets.

Formula & Methodology

1RM is estimated from a weight lifted for reps using formulas such as Epley: 1RM = weight × (1 + reps/30).

Worked Example

Lifting 135 lb for 8 reps estimates a 1RM of about 171 lb.

Frequently Asked Questions

Which formula is best?

Epley, Brzycki, and Lombardi are common. Each gives slightly different results; use one consistently to track progress.

Is an estimated 1RM safe?

Estimating from submaximal lifts is safer than testing a true max. Still, use a spotter and proper form for heavy attempts.

Is this medical advice?

No. Use for training planning. Consult a professional for injury concerns.

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