Estimates 1RM for squat, bench, deadlift and OHP using Epley, Brzycki, Lander, Lombardi, O'Conner formulas. Includes percentage table and standard benchmarks. (Reference for Korean lifters.)
| Formula | Year | Equation | Est. 1RM (kg) |
|---|---|---|---|
| Epley (most common) | 1985 | w × (1 + r/30) | 93.3 |
| Brzycki (≤10 reps accurate) | 1993 | w × 36 / (37 − r) | 90 |
| Lander (mid) | 1985 | w × 100 / (101.3 − 2.67123 × r) | 91 |
| Lombardi (high-rep) | 1989 | w × r^0.10 | 94 |
| O'Conner (conservative) | 1989 | w × (1 + 0.025 × r) | 90 |
| Back Squat | 1.5–2.0× bodyweight |
| Bench Press | 1.0–1.5× bodyweight |
| Deadlift | 1.75–2.5× bodyweight |
| Overhead Press (OHP) | 0.65–0.9× bodyweight |
| Barbell Row | 1.0–1.4× bodyweight |
| 1–5 reps | ±3–5% (most accurate) |
| 6–10 reps | ±5–8% (typical) |
| 11–15 reps | ±10–15% (reference only) |
| 16+ reps | ±20%+ (low confidence) |
This Korea-friendly reference uses standard 1RM estimation formulas (Epley 1985, Brzycki 1993, Lander, Lombardi, O'Conner). 1RM values are statistical estimates; actual maxes vary by individual physique, technique and condition. This tool is not medical or training advice. People with Korean cardiovascular/joint disease, hypertension, diabetes or pregnancy must consult a Korean physician or qualified trainer before attempting a 1RM. Under-16 lifters should not attempt 1RM testing due to skeletal-development risk. Always lift with a spotter, power rack and safety bars, and stop immediately on pain, dizziness or breath difficulty. This tool does not promote any supplement, equipment or training program.
1RM (One Rep Max) is the maximum weight you can lift once with proper form — a standard strength benchmark. Direct testing is risky, so 1RM is usually estimated from a 5–10-rep set. Epley (1RM = w × (1+r/30)) is most popular; Brzycki (1RM = w × 36/(37-r)) is most accurate within 10 reps. Estimates drive working-weight selection in programs like 5×5, 5/3/1 and push-pull. ~75% 1RM (≈10 reps) builds size; ~85% 1RM (≈6 reps) builds strength.
No single formula. Epley is best for 5–10 reps, Brzycki for 1–10 reps; over 11 reps, all formulas drift. Averaging the five reduces individual error.
Not recommended outside coached settings. Estimate from a 5RM or 8RM. Always warm up 40%→60%→80%→90% with a spotter for direct attempts.
Every 4–6 weeks (hypertrophy phase) or 8–12 weeks (strength phase). Frequent testing accumulates neural fatigue.
Yes — formulas are identical. Female averages are typically 60–70% of male averages, but personal progress matters most.
Average adult male: squat 1.5–2.0×, bench 1.0–1.5×, deadlift 1.75–2.5×, OHP 0.65–0.9×. Females: 60–70% of male averages, with wide individual range.
Yes, 80% 1RM blends strength and hypertrophy. Pure hypertrophy is 70–75% (8–12 reps), pure strength 85–95% (1–5 reps).
1RM (One Rep Max) is the maximum weight liftable once with proper form, the standard strength benchmark. This calculator estimates 1RM with five standard formulas: Epley (1985) 1RM = weight × (1 + reps/30); Brzycki (1993) 1RM = weight × 36 / (37 − reps); Lander 1RM = weight × 100 / (101.3 − 2.67123 × reps); Lombardi 1RM = weight × reps^0.10; O'Conner 1RM = weight × (1 + 0.025 × reps). 1–5 reps yields ±3–5% accuracy, 6–10 reps ±5–8%, 11+ reps lose reliability quickly. Estimated 1RM drives working-weight selection (50% ≈25 reps, 60% ≈18, 70% ≈12, 75% ≈10, 80% ≈8, 85% ≈6, 90% ≈4, 95% ≈2, 100% =1). Average adult male benchmarks vs bodyweight: squat 1.5–2.0×, bench 1.0–1.5×, deadlift 1.75–2.5×, overhead press 0.65–0.9×; female averages are 60–70% of male. Direct 1RM attempts carry injury risk: warm up 40%→60%→80%→90%, use a spotter, power rack and safety bars. Korean adults with cardiovascular or joint disease, hypertension, diabetes, or pregnancy must consult a Korean physician or qualified trainer first; under-16 testing is not recommended. This calculator is reference only; consult NSCA, ACSM, the Korean Society of Exercise Physiology, or a qualified trainer for prescriptive programs.