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.

Programming

Wendler 5/3/1

Wendler 5/3/1 is a strength training program created by Jim Wendler in 2008 that uses 4-week waves of percentage-based work on the four main barbell lifts (bench, squat, deadlift, overhead press), with each lift trained once per week.

5/3/1 builds each cycle around the lifter's Training Max (90% of 1RM). Week 1 is 65/75/85% × 5/5/5+; Week 2 is 70/80/90% × 3/3/3+; Week 3 is 75/85/95% × 5/3/1+; Week 4 is a deload at 40/50/60%. The final working set of weeks 1-3 is an AMRAP, providing a built-in progress metric.

The program is a popular choice for intermediate lifters because it advances on monthly waves rather than every-session linear progression — slow but durable. After 3-4 successful cycles, the lifter increases the TM by 5 lb (upper body) or 10 lb (lower body) and starts a new wave. The book "Beyond 5/3/1" extends the original template with variations like Boring But Big, First Set Last, and the Triumvirate.