One Rep Max (1RM) Calculator
Estimate your one-rep max from a weight and number of reps with the Epley, Brzycki and Lombardi formulas, plus a table of training weights from 50% to 100%.
Results
Percentages of 1RM
| % 1RM | Weight | ≈ Reps |
|---|---|---|
| 100% | 115.5 kg | 1 |
| 95% | 109.8 kg | 2 |
| 90% | 104 kg | 3 |
| 85% | 98.2 kg | 5 |
| 80% | 92.4 kg | 8 |
| 75% | 86.7 kg | 10 |
| 70% | 80.9 kg | 13 |
| 65% | 75.1 kg | 16 |
| 60% | 69.3 kg | 20 |
| 55% | 63.5 kg | 25 |
| 50% | 57.8 kg | 30 |
- Epley: w × (1 + reps ÷ 30). Brzycki: w × 36 ÷ (37 − reps). Lombardi: w × reps^0.10. The percentage table uses the average.
What is One Rep Max Calculator?
Estimates the maximum weight you could lift for one repetition from a set you actually performed, using three published formulas and their average. A percentage table shows training weights and approximate reps from 50% to 100% of your 1RM.
How to use One Rep Max Calculator
- Enter the Weight lifted and choose kg or lb.
- Enter the number of Repetitions you completed (1–30).
- Read your estimated 1RM and use the percentage table to plan training loads.
Example
100 kg × 5 reps
Epley 116.7 kg, Brzycki 112.5 kg, Lombardi 117.5 kg; average 115.5 kg
When to use One Rep Max Calculator
Use it to set training percentages without a risky max attempt. Accuracy is best with sets of 3–10 reps taken close to failure; above 10 reps estimates drift and a warning is shown.
How One Rep Max Calculator works
Epley: 1RM = w × (1 + reps ÷ 30). Brzycki: 1RM = w × 36 ÷ (37 − reps). Lombardi: 1RM = w × reps^0.10. With 1 rep the 1RM is the weight itself. The headline value is the average of the three. Approximate reps at each percentage come from inverting Epley: reps ≈ 30 × (100 ÷ % − 1).
Common Use Cases
- Planning a percentage-based program
- Tracking strength progress between tests
- Estimating a bench press, squat or deadlift max
- Choosing weights for a given rep range
FAQs
Which formula is best?
Studies find all three similar for low rep ranges. Epley tends to be higher and Brzycki lower, so the average is a reasonable middle.
Should I test my real 1RM?
Only with experience, warm-ups and a spotter. Estimates are safer for most people.
Does it work for every exercise?
It works best for compound barbell lifts; isolation and machine exercises often allow more reps at a given percentage.