| Formula | 1RM |
|---|
| %1RM | Load | Approx Reps |
|---|
Use this free 1RM calculator to estimate your one-rep max from any set. Choose from proven formulas (Epley, Brzycki, Lombardi, Mayhew, O’Conner, Lander, Wathan) and see %1RM training loads, a training max (90%), and a set planner. Works in kg and lb.
Approximate reps you can perform at each intensity vary by lift and athlete, but a common guide is:
| %1RM | ~Reps | Use case |
|---|---|---|
| 95% | 2 | Peak singles/doubles |
| 90% | 3–4 | Strength triples |
| 85% | 5–6 | Heavy strength work |
| 80% | 6–8 | Main work sets |
| 75% | 8–10 | Hypertrophy focus |
| 70% | 10–12 | Volume / technique |
| 65% | 12–15 | Hypertrophy / accessories |
| 60% | 15+ | Endurance / deload |
A Training Max is typically 90% of true 1RM. It builds progress with less fatigue and is used by systems like 5/3/1. Your calculator displays TM automatically.
Use a spotter for heavy sets, warm up properly, and prioritise technique. If you’re returning from injury, estimate conservatively and progress gradually.
Q: What is a one-rep max (1RM)?
A: The maximum weight you can lift for one complete repetition with standard technique.
Q: Which formula is most accurate?
A: Accuracy depends on lift, rep range and athlete. Comparing several formulas and using the median gives a robust estimate.
Q: Can I calculate 1RM without maxing out?
A: Yes—enter a heavy set (e.g., 5 reps @ RPE 9) and the calculator predicts your 1RM.
Q: Does 1RM differ by lift?
A: Yes. Fatigue and leverage vary. Estimate per lift (squat, bench, deadlift, etc.) and track them separately.
Q: kg or lb—does it matter?
A: The math scales. Just keep inputs and outputs in the same unit and be consistent in your training log.
Q: How often should I retest?
A: Re-estimate every 4–8 weeks, or after a training block. Use the same method to track progress reliably.