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One Rep Max (1RM) Calculator

Estimate your one rep max for any lift using four formulas plus training percentage table.

1-rep max (avg)
115.1 kg
Estimated 1-rep max (avg)
115.1 kg
Average of Epley, Brzycki, Lander & Lombardi
Epley
116.7 kg
Brzycki
112.5 kg
Lander
113.7 kg
Lombardi
117.5 kg

Training percentages

% of 1RMWeightReps
100%115.1 kg1
95%109.3 kg2-3
90%103.6 kg4-5
85%97.8 kg5-6
80%92.1 kg7-8
75%86.3 kg9-10
70%80.6 kg11-12
65%74.8 kg13-15
60%69.1 kg16-20

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    Each calculator is unit-tested against authoritative sources.

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How to use the One Rep Max (1RM) Calculator

  1. 1

    Enter your inputs

    Fill in the required fields at the top of the 1rm calculator. Each input shows a default placeholder so you can see the expected format and units before you type.

  2. 2

    Adjust assumptions and options

    Use the toggles, sliders and dropdowns to tailor the calculation to your situation — currency, country, time period, advanced options and any optional fields all change the result in real time.

  3. 3

    Review the result

    The result card updates instantly as you type. Read the headline number, then check the breakdown, chart and any per-period schedule to understand how the inputs combined to produce the answer.

  4. 4

    Compare scenarios

    Change one input at a time to see how sensitive the result is to that variable. This is how you build intuition: small changes that move the answer a lot are the levers that matter.

  5. 5

    Share or save your result

    Copy the shareable link to send the exact scenario to someone else, or use your browser to print or save the page. The URL preserves every input so the recipient sees the same answer you do.

Frequently Asked Questions

  • One-rep maximum: the heaviest weight you can lift for a single repetition with proper form. Used to set training percentages and benchmark strength.

  • Brzycki and Epley both perform well in 1-10 rep range. Above 10 reps, accuracy declines significantly for all formulas. Average multiple formulas for best estimate.

  • For competitive lifters, periodically yes (with warm-up and spotter). For most people, estimated 1RM from rep work is safer and still very useful for programming.

  • 5x5 strength: 80-85% of 1RM. Hypertrophy: 65-75% × 8-12 reps. Power: 50-70% × 3-5 reps fast. Endurance: 50-60% × 15+ reps.

  • Above 10 reps, muscular endurance and metabolic factors dominate over pure strength. The relationship breaks down — a 30-rep set isn't a meaningful predictor of 1RM.

  • Yes — typical strength ratios (advanced lifter): bench ~ 1.5x bodyweight, squat ~ 2x, deadlift ~ 2.5x, overhead press ~ 0.75x. Use exercise-specific calculators for accuracy.

  • No — only your top set's reps and weight matter for 1RM estimation.

  • Beginners: every 4-6 weeks (rapid progress). Intermediates: every 8-12 weeks. Advanced: when you complete a peaking cycle or hit clear PR rep counts.

  • Bad form inflates weight but increases injury risk and skews future programming. Always test 1RM with strict form, full ROM and ideally a spotter.

  • Use the strength standards table for your selected exercise. Standards range from untrained to elite, scaled to bodyweight.

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