One-Rep Max (1RM) Strength Calculator
Calculate maximum single-rep lift (1RM) using Epley and Brzycki formulas plus workout percentage training zones.
- 100% free
- Private in browser
- No signup
- No watermarks
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About One-Rep Max (1RM) Strength Calculator
Calculate maximum single-rep lift (1RM) using Epley and Brzycki formulas plus workout percentage training zones. Enter Weight Lifted and Repetitions Completed and the tool works out Estimated 1RM, Estimated 1RM and 85% 1RM Heavy Strength Target straight away. Everything runs in your browser, so your data never leaves your device.
How to use One-Rep Max (1RM) Strength Calculator
- Enter Weight Lifted and Repetitions Completed.
- Change any value to see the result update instantly.
- Read Estimated 1RM, Estimated 1RM and 85% 1RM Heavy Strength Target in the results panel — copy or download what you need.
Key features
- Shows Estimated 1RM (Epley Formula)
- Shows Estimated 1RM (Brzycki Formula)
- Shows 85% 1RM Heavy Strength Target
- 2 adjustable inputs, results update as you type
- No signup, no limits
Frequently asked questions
- Is this calculation free and private?
- Yes, 100% of calculations execute locally in your web browser. No inputs or personal data are stored or transmitted.
- What does the One-Rep Max (1RM) Strength Calculator give me?
- It works out Estimated 1RM, Estimated 1RM, 85% 1RM Heavy Strength Target and 70% 1RM Hypertrophy Volume Target, updating live as you change the inputs.
- What do I need to enter?
- Just Weight Lifted and Repetitions Completed. Every field has a sensible default you can start from.
- Is my data uploaded anywhere?
- No. The calculation runs in your browser with JavaScript — nothing you type is sent to a server or stored.
- Does it work on a phone?
- Yes. The layout adapts to small screens and needs no app or signup.
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