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Strength Calculator
Calculate your one-rep max and assess your strength level compared to others.
- Enter the maximum weight you can lift for the given number of reps
- Use your most recent personal best for accuracy
- Ensure proper form was maintained throughout the lift
- For best results, use rep ranges between 1-10
How your one-rep max is estimated
Your one-rep max (1RM) is the most weight you could lift for a single rep. You don't need to actually attempt it — that carries real injury risk — because the relationship between reps and load is predictable enough to estimate. Feed in a heavy set you've already done and a prediction formula does the rest.
Rather than rely on one equation, this calculator averages three well-established ones, because each rounds slightly differently:
- Epley: weight × (1 + reps ÷ 30)
- Brzycki: weight × 36 ÷ (37 − reps)
- Lombardi: weight × reps0.1
All three are most reliable at low reps. A heavy set of 3–6 reps gives a tight estimate; high-rep sets to failure drift because endurance varies so much from lifter to lifter.
What strength standards mean
A 100 kg bench means something very different for a 60 kg lifter than for a 120 kg one, so strength is measured relative to bodyweight — your estimated 1RM divided by what you weigh. This calculator bands that ratio into five levels, the same scale used across the lifting world:
- Untrained: hasn't trained the lift before.
- Novice: a few months of regular training.
- Intermediate: one to a couple of years in.
- Advanced: several years of consistent, structured work.
- Elite: competitive strength-athlete territory.
The Strength Standards tab above lists the exact bodyweight ratios for the bench, squat, deadlift, and overhead press, for both men and women.
Worked example
An 80 kg (176 lb) man benches 100 kg for 5 reps:
- Epley: 100 × (1 + 5/30) ≈ 117 kg
- Brzycki: 100 × 36/(37−5) ≈ 113 kg
- Lombardi: 100 × 50.1 ≈ 117 kg
- Averaged 1RM ≈ 116 kg
- Ratio = 116 ÷ 80 ≈ 1.45× bodyweight → Intermediate, approaching Advanced (1.5×)
How to actually move up a level
Strength is built on progressive overload — adding a little weight or a rep over time so the work keeps getting harder. Anchor your training in the big compound lifts, run a program for at least 8–12 weeks before judging it, and eat enough to recover: strength stalls fast on too little food or sleep. Fuelling matters as much as the lifting — get your maintenance calories right, lean slightly into a surplus if you're chasing numbers, and hit your protein. For the full picture, see how to build muscle.
Frequently asked questions
How is one-rep max (1RM) calculated from a set of reps?
You don't have to lift a true max to estimate it. From the weight you lifted and the reps you completed, prediction formulas estimate the most you could lift once. This calculator runs three published formulas — Epley, Brzycki, and Lombardi — and averages them, which smooths out the quirks of any single equation. For example, 100 kg for 5 reps estimates roughly a 113–118 kg one-rep max.
How accurate are estimated one-rep maxes?
They're most accurate at low reps. Below about 5–6 reps the estimate is usually within 5% of your true max; as reps climb past 10, fatigue and individual endurance vary so much that the prediction drifts. For the best estimate, use a heavy set of 3–6 clean reps rather than a high-rep set taken to failure.
What's a good bench, squat, or deadlift for my bodyweight?
Strength is judged relative to bodyweight. For men, a rough intermediate benchmark is bench pressing about 1× bodyweight, squatting 1.25×, and deadlifting 1.5×; advanced lifters reach roughly 1.5× bench, 1.75× squat, and 2× deadlift. Women's ratios run lower because of differences in muscle mass. The Strength Standards tab on this page lists the full Untrained-to-Elite bands by lift and sex.
How long does it take to go from novice to intermediate?
With consistent training, most people reach intermediate standards within their first 1–2 years. Beginners make the fastest gains — often adding weight every session through 'newbie gains' — then progress slows and requires more structured programming. Genetics, age, recovery, and nutrition all shift the timeline.
Should I actually test my true one-rep max?
Usually no. Estimating from a 3–5 rep set is safer and nearly as informative. A true 1RM attempt carries real injury risk and should only be done occasionally, fully warmed up, with experienced spotters or safety bars. For tracking progress, the estimated max from this calculator is the practical choice.
Sources: Epley B (1985); Brzycki M (1993); Lombardi VP (1989) one-rep-max prediction equations. Strength standards are bodyweight-ratio bands commonly used in resistance-training practice.
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