How accurate are 1RM calculators?

1RM calculators are generally accurate within 5-10% when used with rep ranges under 10. The accuracy depends on factors like training experience, muscle fiber composition, and the specific formula used. Our calculator uses 7 different formulas to give you the most comprehensive estimate.

Which 1RM formula is most accurate?

The Epley formula is most widely used and accurate for most people, especially with rep ranges of 2-10. However, different formulas work better for different individuals. Brzycki tends to be conservative, while Lombardi works well for powerlifters. Our calculator shows all 7 formulas so you can compare.

Can I use this for any exercise?

Yes, you can use 1RM calculators for any compound exercise like bench press, squat, deadlift, overhead press, and rows. The formulas are based on general strength principles that apply across exercises, though they're most accurate for compound movements.

What rep range should I use for the most accurate calculation?

For best accuracy, use rep ranges between 2-10 reps. The sweet spot is 3-8 reps where most formulas perform optimally. Avoid using very high rep ranges (15+) as the formulas become less reliable due to muscular endurance factors.

How often should I recalculate my 1RM?

Recalculate your 1RM every 4-6 weeks or whenever you notice significant strength gains. For beginners, monthly calculations work well. Advanced lifters might recalculate every 6-8 weeks. Always use recent max effort sets for the most accurate results.

Wilks Score — Strength Training Glossary

Wilks Score

Wilks Score is a coefficient-based scoring system that adjusts a powerlifter's total for bodyweight and sex, allowing comparison across weight classes.

The original Wilks formula was developed by Robert Wilks in the 1990s; Wilks 2 (2020) is the modernized version with updated polynomial coefficients. The score is calculated by multiplying the lifter's total (squat + bench + deadlift) by 600 and dividing by a fifth-degree polynomial of bodyweight in kilograms.

A Wilks score of 400+ is intermediate-to-advanced; 470+ is regional/national level; 525+ approaches world-class. Wilks 2 has been largely replaced by IPF GL Points (in international powerlifting) and DOTS (in USAPL and other federations), but is still common on training-log platforms.

Wilks Score

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