One-Rep Max (1RM) Calculator
Estimate the maximum weight you can lift for a single repetition from a submaximal effort. Never test a true 1RM without a spotter and proper warm-up.
Estimated 1RM
This tool is for informational purposes only and does not constitute medical advice. Consult a certified strength and conditioning specialist (CSCS) before designing a heavy lifting program.
NSCA Strength Standards Reference
| Lift | Novice (M/F) | Intermediate (M/F) | Advanced (M/F) |
|---|---|---|---|
| Back Squat | 1.0 / 0.75× BW | 1.5 / 1.1× BW | 2.0 / 1.5× BW |
| Bench Press | 0.75 / 0.5× BW | 1.25 / 0.8× BW | 1.75 / 1.1× BW |
| Deadlift | 1.25 / 1.0× BW | 1.75 / 1.25× BW | 2.5 / 1.75× BW |
| Overhead Press | 0.5 / 0.35× BW | 0.75 / 0.5× BW | 1.1 / 0.7× BW |
BW = bodyweight. Standards adapted from NSCA for recreational and competitive athletes.
Formula Comparison
| Formula | Equation | Best For |
|---|---|---|
| Brzycki | w ÷ (1.0278 − 0.0278 × r) | 1–10 reps; slightly conservative |
| Epley | w × (1 + r ÷ 30) | Higher rep ranges; tends to over-estimate at low reps |
| Lander | (100 × w) ÷ (101.3 − 2.67123 × r) | General use; performs well 2–14 reps |
References & Methodology
- Brzycki, M. (1993) — "Strength Testing — Predicting a One-Rep Max from Reps-to-Fatigue." Journal of Physical Education, Recreation & Dance 64(1):88-90. Most widely cited prediction formula.
- Haff, G. G., & Triplett, N. T. (Eds.) (2016) — Essentials of Strength Training and Conditioning, 4th ed. NSCA / Human Kinetics. Authoritative reference for strength standards and programming.
- Mayhew, J. L., et al. (1995) — "Muscular endurance repetitions to predict bench press strength in men of different training levels." Journal of Sports Medicine and Physical Fitness 35(2):108-13. Multi-formula validation study.