1RM Calculator
Plan your training weights
Estimate Your 1 Rep Max
Enter a recent, near-failure set to estimate your true one rep max and see how it stacks up against strength standards for your gender and body weight.
How This Calculator Works
Your one rep max (1RM) is the heaviest weight you can lift for a single, full-range rep with good form. Rather than testing that number directly — which is taxing on the body and risky without supervision — this calculator estimates it from a submaximal set you can perform safely, using three well-known formulas (Epley, Brzycki, and Lombardi) and averaging them for a more reliable estimate.
For the most accurate estimate, use a set taken close to failure — one where you could not have completed more than a rep or two beyond what you recorded — and keep the rep count low, ideally 3 to 5 reps. Estimation formulas lose accuracy at very high rep counts, and fatigue or breakdown in technique on later reps can also skew the result, so prioritise a clean, well- controlled set over chasing extra reps.
Estimates only — actual 1RM varies with technique, fatigue, and training history. Never attempt a true 1RM without a spotter and a proper warm-up; heavy strength training carries a real risk of injury. Consult a fitness professional before attempting heavy lifts, especially if you are a beginner or have any pre-existing injury.
Fuel Your Training
Knowing your training loads is only half the picture — make sure your calorie and protein intake can support the work you're about to put in.
Calculate Your Calories