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.

Contact Us

Email Support

For general inquiries, feature requests, or technical support:

support@1rmcalculator.com

We typically respond within 24-48 hours

Response Time

We aim to respond to all inquiries quickly:

• General inquiries: 24-48 hours
• Bug reports: 12-24 hours
• Feature requests: 3-5 business days

How Can We Help?

Technical Support

Having trouble with calculations? Getting unexpected results? We're here to help troubleshoot any technical issues.

Feature Requests

Have an idea for a new feature? We love hearing from our users about how we can improve the calculator.

Report a Bug

Found something that isn't working right? Let us know and we'll fix it as soon as possible.

Partnership Inquiries

Interested in partnering with us or integrating our calculator into your platform? Let's talk.

Frequently Asked Questions

Is the calculator really free?

Yes! Our calculator is 100% free to use. No hidden fees, no premium version, no sign-ups required. We believe in providing value to the lifting community.

How accurate are the calculations?

We use 7 scientifically validated formulas and average them for accuracy. Results are typically within 5% of actual 1RM for most lifters. Individual variation may occur based on training experience and muscle fiber composition.

Can I use this for all exercises?

Our calculator works best for compound barbell movements like squat, bench, and deadlift. It can be used for other exercises but may be less accurate for isolation movements or machine exercises.

Do you store my data?

No. We don't collect or store any personal data or lifting numbers. Your unit preference (kg/lb) is saved locally in your browser for convenience, but no data leaves your device.

Quick Message

For the fastest response, please email us directly at support@1rmcalculator.com

Include as much detail as possible about your question or issue, including:

• The exercise you were calculating
• The weight and reps you entered
• Any error messages you saw
• Your browser and device type