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.

Privacy Policy

Last updated: January 2026

Privacy at a Glance

No Data Collection

We don't collect, store, or track your personal information or lifting data.

No Tracking

We don't use analytics, tracking pixels, or advertising cookies.

Information We Don't Collect

We believe in privacy by design. Here's what we don't collect:

• Personal Information: No names, emails, phone numbers, or addresses
• Lifting Data: Your weights, reps, and 1RM calculations stay on your device
• Usage Analytics: We don't track how you use the calculator
• Location Data: We don't access or store your geographic location
• Device Information: We don't collect device IDs or specifications
• Browsing History: We don't track what pages you visit or when

What We Do Use

Local Storage

We use your browser's local storage to save your unit preference (pounds or kilograms). This data never leaves your device and helps provide a better user experience.

You can clear this data anytime through your browser settings.

Third-Party Services

Our website is built using modern web technologies but doesn't rely on third-party services that collect data:

• No Google Analytics: We don't use any analytics services
• No Social Media Tracking: No Facebook Pixel, Twitter tracking, etc.
• No Advertising Networks: No ad tracking or remarketing cookies
• No CDNs with Tracking: We host our assets without tracking

Data Security

Since we don't collect data, there's no personal data to secure. However, we take security seriously:

• HTTPS Encryption: All traffic to our site is encrypted
• No Data Breach Risk: Can't lose what we don't collect
• Regular Updates: We keep our infrastructure secure and updated
• No Account System: No passwords or login credentials to compromise

Your Rights

Because we don't collect personal data, many traditional privacy rights don't apply. However:

• Right to Privacy: You maintain complete privacy while using our calculator
• Right to Control: All data stays on your device under your control
• Right to Delete: Clear your browser's local storage to remove unit preferences
• Right to Know: This policy explains exactly what we do and don't do

Children's Privacy

Our calculator is safe for users of all ages because we don't collect any personal information. Parents can feel confident that their children's privacy is protected when using our tool.

Changes to This Policy

We may update this privacy policy from time to time. Any changes will be posted on this page with an updated revision date. Since we don't collect contact information, we can't notify you directly of changes.

We encourage you to review this policy periodically to stay informed about how we protect your privacy.

Questions About Privacy?

If you have any questions about this privacy policy or our privacy practices, please contact us:

privacy@1rmcalculator.com