Strength & Lifting

    One Rep Max Calculator

    Calculate your estimated one rep max (1RM) using three validated formulas. Get a full rep-max table, training zones, and see where you rank against strength standards.

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    Updated March 2026
    Epley · Brzycki · Lombardi formulas · Strength standards by bodyweight
    James MitchellWritten by James Mitchell
    Updated March 30, 2026

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    Last Updated: March 2026

    How do I calculate my one rep max?

    Your one rep max (1RM) is estimated using a submaximal lift: weight lifted × (1 + reps ÷ 30) using the Epley formula, or weight ÷ (1.0278 − 0.0278 × reps) using Brzycki. For example, 200 lbs for 5 reps estimates to approximately 233 lbs 1RM by Epley. Most accurate with 3–6 rep sets.

    What is a good one rep max for bench press?

    For intermediate male lifters, a bodyweight bench press (1.0× BW) is a standard milestone. Advanced is 1.5× bodyweight. Elite is 2.0× bodyweight or more. For women, intermediate is 0.75× bodyweight. These standards are based on bodyweight ratio data from the National Strength and Conditioning Association (NSCA).

    How accurate is a 1RM calculator?

    The Epley and Brzycki formulas are most accurate for 1–6 reps, with error rates under 5% for well-trained individuals. Accuracy decreases above 8 reps because cardiovascular fatigue - not muscle strength - becomes the limiting factor. Always test with a heavy 3–5 rep set for best accuracy.

    How often should I test my 1RM?

    Beginners and intermediates should test their 1RM every 8–12 weeks, typically at the end of a training block. Testing too frequently increases injury risk and disrupts training. Using submaximal rep tests (5RM, 3RM) to estimate 1RM is a safer way to track strength progress between dedicated test sessions.

    One Rep Max: The Complete Science Guide

    Your One Rep Max (1RM) is the maximum amount of weight you can lift for exactly one complete repetition with proper technique on a given exercise. It's the fundamental unit of strength measurement and the cornerstone of all serious strength training programming.

    Whether you follow 5/3/1, Wendler, Conjugate, Sheiko, or any other percentage-based program, your training loads are prescribed as percentages of your 1RM. Knowing your accurate 1RM is essential for programming intelligently.

    The Three 1RM Formulas Explained

    1. Epley Formula (1985) - Primary Recommendation
    1RM = weight × (1 + reps / 30)

    Published by Boyd Epley (University of Nebraska strength coach) in 1985. The most widely used formula worldwide - it's the default in most gym software, apps, and strength calculators. Accurate within 2–4% for sets of 1–10 reps. Slightly overestimates at higher rep counts.

    2. Brzycki Formula (1993)
    1RM = weight × (36 / (37 − reps))

    Developed by Matt Brzycki (Princeton University). Considered slightly more accurate than Epley for sets in the 1–8 rep range. Because it uses subtraction rather than addition, it more severely penalizes higher rep counts - making it less suitable above 10 reps (denominator approaches zero).

    3. Lombardi Formula
    1RM = weight × reps^0.10

    Uses an exponential relationship between reps and weight. Tends to produce lower estimates than Epley and Brzycki, making it useful as a conservative lower bound. Particularly well-suited for higher rep ranges (8–12) where the other formulas overestimate.

    Formula Accuracy Comparison

    FormulaBest AccuracyOverestimates?Recommendation
    Epley (1985)1–10 repsSlightly at 10+⭐ Default - most popular, most validated
    Brzycki (1993)1–8 repsYes above 10Best for low-rep max attempts
    Lombardi6–12 repsUsually underConservative estimate, good for hypertrophy ranges

    Training Percentage Reference Guide

    Once you have your 1RM, use these percentages to select appropriate training loads for different fitness goals:

    90–100%
    Max Strength · 1–3 reps

    Neural adaptation, max effort. Use 1–2× per month maximum.

    80–90%
    Strength · 3–6 reps

    Core of powerlifting programs. High intensity, high specificity.

    70–80%
    Strength-Hypertrophy · 6–10 reps

    Best balance of strength and muscle gain. Most common zone.

    60–70%
    Hypertrophy · 10–15 reps

    Muscle growth focus. Volume is the key driver here.

    < 60%
    Endurance · 15+ reps

    Muscular endurance. Limited strength/hypertrophy stimulus.

    How to Safely Estimate Your 1RM

    Actual max testing is risky for most lifters. Instead, use this 5-step protocol to safely measure your estimated 1RM:

    • Step 1 - Warm up properly: Start with 2–3 light sets (50%, 65%, 75% of expected max) with plenty of rest between each.
    • Step 2 - Work up to a heavy set: Perform 1–2 more sets at 85–90% of your expected max to prime your nervous system.
    • Step 3 - Choose your test set: Select a weight you expect to hit for 3–5 clean reps. This is your measurement set.
    • Step 4 - Max effort reps: Perform as many quality reps as possible (stop at the first technical breakdown, don't grind ugly reps).
    • Step 5 - Enter into calculator: Plug your weight and reps into this calculator for your estimated 1RM.

    Pro tip: The most accurate estimates come from 3–5 rep sets. Beyond 8 reps, all formulas lose accuracy because fatigue becomes a limiting factor alongside pure strength.

    Strength Standards by Exercise

    Strength standards are based on your 1RM relative to bodyweight. Dive deeper with the dedicated calculators for Bench Press, Squat, and Deadlift - or see how you rank across all lifts with the Strength Standards Checker. Here are the benchmarks for the four major barbell lifts (male, ~185 lb / 84 kg bodyweight):

    ExerciseBeginnerNoviceIntermediateAdvancedElite
    Bench Press0.5×0.75×1.25×1.75×2.2×
    Squat0.75×1.25×1.5×2.0×2.5×
    Deadlift1.0×1.5×2.0×2.5×3.0×
    Overhead Press0.35×0.55×0.8×1.1×1.4×

    × = multiples of bodyweight. Source: Strength Level, ExRx, and competitive powerlifting classification systems. Female standards are approximately 30–40% lower across all exercises.

    Sources & References

    1. Epley B. Poundage chart. Boyd Epley Workout. Lincoln: University of Nebraska; 1985.
    2. Brzycki M. Strength testing: predicting a one-rep max from reps-to-fatigue. J Phys Ed Recreat Dance. 1993;64(1):88-90.
    3. Mayhew JL, et al. Accuracy of prediction equations for estimating 1-RM performance in the bench press. J Strength Cond Res. 1992;6(2):97-101.
    4. National Strength and Conditioning Association. Essentials of Strength Training and Conditioning. 4th ed. Human Kinetics; 2016.

    One Rep Max Calculator - Frequently Asked Questions

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