Which formula is best?
Epley is popular for 1–10 reps; try a few and see which matches your lifts.
One Rep Max Calculator
Enter a heavy set (weight × reps) to estimate your 1RM for program planning.
Weight and reps
Use a recent hard set between 1–10 reps for best accuracy.
About this calculator
How to use One Rep Max Calculator, plus the formulas and logic behind the results.
Tool description
A one-rep max is the heaviest weight you can lift once with good form. Submaximal formulas predict it without a risky true max attempt.
How to use
- Pick Epley, Brzycki, or Lombardi.
- Enter weight and reps from a recent working set.
- Calculate estimated 1RM.
- Use 85–95% of estimate for training, not ego maxing daily.
Formulas & reference
Epley: 1RM = weight × (1 + reps÷30)Brzycki: 1RM = weight ÷ (1.0278 − 0.0278×reps)Lombardi: 1RM = weight × reps^0.10
Typical training percentages
- 90%: heavy singles
- 80–85%: strength sets of 3–5
- 70–75%: volume work
- 60%: technique / warm-up loads
Calculation logic
Selected formula converts submaximal performance to predicted 1RM. Lower reps (≤10) generally yield tighter estimates.
Estimates differ by lift, lifter, and fatigue. Always use spotters on true max tests.
One Rep Max Calculator FAQ
Common questions about this calculator and how to use the results.
Can I use dumbbells?
Yes—enter total weight per hand ×2 if both hands move together, or per-arm for single-arm work and note context.
Are high-rep sets OK?
Above ~10 reps, predictions get noisier; use lower-rep sets when possible.
Should beginners max out?
No need—submaximal estimates are safer while learning form.
Same 1RM for squat and bench?
No—calculate each lift separately.
Deload weeks?
Use recent pre-deload numbers or expect lower estimates when fatigued.