One Rep Max Calculator
Estimate your one-rep maximum (1RM) for any lift — bench press, squat, deadlift — from a submaximal effort. Calculate training percentages for progressive overload.
Part of our Health Calculators collection.
One Rep Max Calculator
Free online calculator
For best accuracy use 1–10 reps
Results update automatically as you type
How to Use This Calculator
- 1
Enter the weight you lifted.
- 2
Enter how many reps you completed.
- 3
Select the formula (Epley is most widely used).
- 4
See your estimated 1RM and training percentages.
One Rep Max Formulas
Epley: 1RM = weight × (1 + reps/30) Brzycki: 1RM = weight × (36 / (37 − reps)) Training percentages: 100% = 1RM (max effort) 90% = 3–4 reps 80% = 6–8 reps (hypertrophy range) 70% = 10–12 reps 60% = 15–20 reps
Example Calculation
Example: 225 lbs for 5 reps (bench press)
Inputs
weight: 225reps: 5formula: epley
Result
Estimated 1RM: ~262 lbs
Epley: 225 × (1 + 5/30) = 225 × 1.167 = 262.5 lbs.
Frequently Asked Questions
How accurate is the 1RM calculator?
For 1–6 rep tests, accuracy is typically within 5–10% of actual 1RM. Accuracy decreases significantly for higher rep counts (10+). Never attempt an actual 1RM without a spotter and proper warm-up.
What percentage should I use for hypertrophy?
Most research shows 65–85% of 1RM (roughly 6–12 reps) is optimal for muscle hypertrophy. Anything from 30% to 85% can build muscle if taken to near-failure.