Estimate your max lift — weight in any unit, result follows.
1RM = w × (1 + r / 30)
The Epley formula is one of the most widely cited and validated methods for estimating one-rep max from a submaximal lift. It was published by Boyd Epley in 1985 and remains a standard in strength and conditioning.
The formula works best when the number of reps performed is between 2 and 10. Accuracy decreases above 10 reps because the set becomes more metabolically demanding and less indicative of pure strength.
1RM = 185 × (1 + 6 / 30) = 185 × (1 + 0.2) = 185 × 1.2 = 222 lbs
Result: Estimated One Rep Max ≈ **222 lbs**
In this example, a lifter who completed 6 reps at 185 lbs has an estimated one-rep max of 222 lbs.
This means that, in theory, they could perform a single maximum-effort repetition with 222 lbs. In practice, this is an estimate — actual performance on the day can vary due to fatigue, technique, rest periods, and mental readiness.
To use this result in training:
One Rep Max is the gold standard for measuring absolute strength. It's used by powerlifters, Olympic weightlifters, and everyday gym-goers alike to:
Boyd Epley introduced this formula in 1985 as part of the University of Nebraska strength program. Among the many 1RM prediction equations (Brzycki, Lander, O'Conner, Mayhew), the Epley formula consistently performs well in peer-reviewed validation studies.
Other common formulas:
Small differences between these formulas exist, especially at higher rep ranges. For practical training purposes, any validated equation is sufficient.
Always use proper form, adequate warm-up sets, and a qualified spotter or safety equipment (power rack pins) when working with heavy loads near your estimated maximum.
Common training percentages: 1–3 reps = 90–100% of 1RM (maximal strength), 4–6 reps = 80–90% (strength), 6–12 reps = 65–80% (hypertrophy), 12–20 reps = 50–65% (muscular endurance). These are guidelines — individual response varies.
A **1RM** is the absolute maximum weight for one rep. A **training max** (used in programs like 5/3/1) is typically set at 85–90% of your true 1RM to provide a conservative base for programming, reducing injury risk and allowing room for progression.
Both are widely validated. The Brzycki formula (1RM = w × 36 / (37 − r)) tends to give slightly lower estimates at higher rep ranges compared to Epley. For sets of 2–6 reps, the two formulas produce very similar results. Either is suitable for practical training purposes.
Yes. The Epley formula is not sex-specific — it applies equally to men and women. The formula simply uses the weight lifted and reps completed. Absolute strength levels differ between sexes, but the mathematical relationship between submaximal performance and 1RM is similar.
Strength standards vary by bodyweight, sex, age, and training experience. As a general benchmark, intermediate male lifters often achieve a bench press 1RM of ~1× bodyweight, a squat of ~1.5×, and a deadlift of ~2×. Use your estimated 1RM alongside a strength standards chart for a more personalized comparison.
Research shows the Epley formula is accurate within approximately 5–10% for most lifters when reps are kept between 2 and 10. Accuracy decreases significantly for sets above 10 reps. Individual factors like muscle fiber type and training age also affect precision.
Yes — the Epley formula applies to any barbell or resistance exercise. It is most commonly used for the squat, bench press, and deadlift, but also works for overhead press, rows, and other compound lifts. Isolation exercises (e.g., bicep curls) are less commonly tested for 1RM.
Not necessarily, especially for beginners. Performing a true 1RM test carries injury risk if not executed properly. For most training purposes, an estimated 1RM from a submaximal set is sufficient for programming. Advanced lifters and competitive powerlifters may periodically test true 1RM in a controlled setting.
Most strength programs recommend recalculating your training maxes every 4–12 weeks, or at the end of a training block. Recalculating more frequently is unnecessary unless you have made a significant jump in strength.
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