What is the best rep range for estimating 1RM?

Sets of 3 to 5 repetitions offer the highest correlation with actual 1RM strength. Formulas become progressively less accurate for sets exceeding 10 repetitions due to muscular endurance factors.

Updated: August 2026 • Verified v1.2

One-Rep Max (1RM) Weightlifting & Powerlifting Calculator

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Brzycki: W * (36 / (37 - r)); Epley: W * (1 + r/30); Lombardi: W * r^0.10; Avg = (Brz + Epl + Lom) / 3

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Understanding Your Results

Calculates ensemble 1RM single using Brzycki, Epley, and Lombardi clinical formulas, and provides a complete percentage training table (50% to 95%) with recommended rep ranges for strength, hypertrophy, and volume cycles.

Practical Guidance & Next Steps

Submaximal testing with 3 to 6 repetitions provides the most statistically reliable 1RM prediction while minimizing central nervous system fatigue.

What is this?

A strength and conditioning utility that estimates maximum single-repetition lift capacity from submaximal lifting sets.

How does it work?

1. Select exercise and enter weight lifted (lbs or kg). 2. Select repetitions completed (1 to 15 reps). 3. View estimated 1RM, formula breakdown, and percentage training zones.

Why use it?

Allows athletes to program progressive overload training cycles safely without risking heavy single-rep failure injuries.

Technical Scope & Calculation Limitations

Calculates 1RM estimates for 1 to 15 repetitions.

Frequently Asked Questions

The Brzycki and Epley formulas are the two most validated formulas in sports science. For sets under 10 repetitions, they typically estimate within 2% to 3% of an athlete's actual tested 1-rep max.

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