One Rep Max Calculator
Calculate your maximum strength for a single repetition.
Lift Information
Training Percentages
| % of 1RM | Weight | Est. Reps |
|---|---|---|
| 50% | 56 lbs | 23+ |
| 55% | 62 lbs | 19-22 |
| 60% | 68 lbs | 16-18 |
| 65% | 73 lbs | 13-15 |
| 70% | 79 lbs | 11-12 |
| 75% | 84 lbs | 8-10 |
| 80% | 90 lbs | 6-7 |
| 85% | 96 lbs | 4-5 |
| 90% | 101 lbs | 2-3 |
| 95% | 107 lbs | 1 |
| 100% | 113 lbs | 1 |
1RM Estimate
One Rep Max
113
pounds
Based on
100 lbs × 5 reps
Formula
brzycki
Training Zones:
Strength: 101-107 lbs
Hypertrophy: 79-96 lbs
Endurance: 56-73 lbs
About This Calculator
The One Rep Max (1RM) Calculator helps you estimate your maximum strength for a single repetition based on the weight you can lift for multiple reps. Knowing your 1RM is useful for program design, tracking strength progress, and determining training loads.
The calculator uses various formulas (Brzycki, Epley, Lander, etc.) to estimate your 1RM. Different formulas may give slightly different results, with Brzycki being one of the most popular. The calculator also shows training percentages based on your estimated 1RM.
Formula & Calculation Method
One Rep Max Calculation Formulas:
Brzycki: 1RM = Weight ÷ (1.0278 - 0.0278 × Reps)
Epley: 1RM = Weight × (1 + Reps ÷ 30)
Lander: 1RM = (100 × Weight) ÷ (101.3 - 2.67123 × Reps)
Lombardi: 1RM = Weight × Reps^0.1
Mayhew: 1RM = (100 × Weight) ÷ (52.2 + 41.9 × e^(-0.055 × Reps))
O'Conner: 1RM = Weight × (1 + Reps ÷ 40)
Wathan: 1RM = (100 × Weight) ÷ (48.8 + 53.8 × e^(-0.075 × Reps))
The Brzycki formula is one of the most commonly used and accurate for most people. Different formulas may be more accurate for different rep ranges or individuals. The calculator provides multiple options so you can compare estimates.
How to Use This Calculator
- Enter Weight: Input the weight you lifted in pounds (or kg, adjust accordingly).
- Enter Reps: Input the number of repetitions you completed with that weight.
- Select Formula: Choose a 1RM formula (Brzycki is recommended for most cases).
- View Results: See your estimated 1RM and training percentages for different intensities.
Frequently Asked Questions
Which 1RM formula is most accurate?
The Brzycki formula is widely considered one of the most accurate for general use. However, accuracy can vary by individual and rep range. For lower reps (1-5), most formulas are fairly accurate. For higher reps (10+), estimates become less reliable.
How often should I test my actual 1RM?
Actual 1RM testing is physically demanding and should be done sparingly (every 3-6 months). Use estimated 1RM from submaximal loads for regular program adjustments. Always use proper form and have a spotter when testing true 1RM.
What percentage of 1RM should I train at?
Training percentages vary by goal: Strength (85-95% 1RM, 1-5 reps), Hypertrophy (65-85% 1RM, 6-12 reps), Endurance (50-65% 1RM, 15+ reps). Most programs use 70-85% for general strength training.
Can I use this for all exercises?
1RM formulas work best for compound movements (squat, bench, deadlift) where form is consistent. They're less accurate for isolation exercises or movements where technique significantly affects performance.
Calculator by
NumCalculators Editorial Team
Multi-disciplinary Expert Team