Which formula is most accurate?

The Epley and Brzycki formulas are the most popular and generally consider accurate for reps below 10. Accuracy decreases for higher rep ranges (15+).

Calculating your 1RM is much safer than testing it physically. However, these are estimates. Always use a spotter when attempting heavy lifts.

Can I use it for any exercise?

It works best for compound movements like squats, deadlifts, and bench press. It is less accurate for isolation exercises.

One Rep Max Calculator

Calculate your one-rep max (1RM) for any lift. Includes training percentages.

1rmone rep maxmax liftbench press calculator

Disclaimer: This tool provides estimates for informational and educational purposes only. It does not constitute professional financial, medical, or legal advice. Please consult with a qualified professional before making any significant decisions based on these estimations.

Common Use Cases

general awareness and educational estimates
wellness planning alongside professional guidance
tracking simple ranges over time

What is One Rep Max Calculator?

The One Rep Max (1RM) Calculator estimates the maximum weight you can lift for a single repetition based on a weight you lifted for multiple reps. It uses standard formulas (Epley, Brzycki, etc.) to give you a safe estimate without the need to test a true max, which helps prevent injury. It also provides a percentage breakdown to help you plan your training sessions.

How to Use This Tool

1Enter weight lifted and number of repetitions
2View your estimated 1RM
3See training percentages for your max

Example

Input

Weight: 100kg, Reps: 5

Output

1RM: 115kg

Before You Rely on This Result

UtilityNest keeps tools in this category focused on transparency: short instructions, a worked example, and plain-language guidance so you can review the result before you depend on it.

Check that the inputs reflect your real situation before you rely on the estimate.
Rules, rates, health needs, and legal requirements may vary by country, state, insurer, or provider.
Use this result as a starting point, then confirm important decisions with official sources or a qualified professional.

Frequently Asked Questions

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