One Rep Max Calculator
Estimate your 1RM from any set
One Rep Max Calculator
Example: 225 lbs × 5 reps
Epley formula · an estimate from a set taken close to failure; accuracy depends on the exercise and the person and drops as reps grow
225 × (1 + 5 ÷ 30) = 262.5 lbs
comparison of methods: six other published formulas give 253.1–267.8 lbs
Epley: 1RM = weight × (1 + reps ÷ 30); a true maximal single is the 1RM itself
See Also
- BMI Meaning - Check what given BMI means
- BMI Calculator (Imperial) - Body Mass Index Calculator (ft/in/lbs)
- BMI Calculator (Metric) - Body Mass Index Calculator (kg/cm)
- Ideal Weight Calculator (Imperial) - Find out the Ideal Weight for a given Height in feet/inches
- Ideal Weight Calculator (Metric) - Find out the Ideal Weight for a given Height in centimeters
FAQ
What is a one rep max?
Your one rep max (1RM) is the heaviest weight you can lift for a single repetition of an exercise with good form. Because testing it directly is risky, it is normally estimated from a lighter set taken close to failure.
Which formula does this calculator use?
The answer uses the Epley formula: 1RM = weight × (1 + reps ÷ 30). Six other published formulas — Brzycki, Lombardi, O'Conner, Wathan, Lander and Mayhew — are compared with it: the page shows the lowest and the highest of their estimates.
How accurate is an estimated 1RM?
It is an estimate from a set taken close to failure, not a tested max. Its accuracy depends on the exercise and the person, and it drops as the rep count grows, because endurance starts to matter more than maximal strength.
Does it work with kilograms as well as pounds?
Yes. Every 1RM formula is a ratio, so the estimate comes out in the same unit you entered. Pick pounds or kilograms and the answer, the rep table and the training percentages all follow that unit.