🏋️ ONE REP MAX CALCULATOR

One Rep Max (1RM) is the gold standard for measuring maximal strength in weightlifting. Whether you're a powerlifter, bodybuilder, or general fitness enthusiast, knowing your 1RM for exercises like bench press, squat, deadlift, or overhead press helps program accurate training loads. This One Rep Max Calculator uses scientifically validated formulas to estimate the maximum weight you can lift for a single repetition based on a submaximal effort (e.g., 5 reps or 10 reps). It's safer than testing a true 1RM directly, reducing injury risk.

The calculator implements three popular estimation models: Epley (1RM = weight × (1 + reps/30)), Brzycki (weight × 36 / (37 - reps)), and Lombardi (weight × reps^0.10). Each gives slightly different results; powerlifters often prefer Epley for bench and squat, while Brzycki may be more accurate for higher rep ranges. Our tool automatically updates your 1RM as you adjust weight, reps, or formula — no page reload needed.

Understanding your one rep max allows you to set strength standards, calculate training percentages (e.g., 70% of 1RM for hypertrophy), and track progress over time. Athletes in sports like strongman, CrossFit, and weightlifting rely on 1RM for periodization. Always use proper form and a spotter when attempting heavy loads. This tool is optimized for mobile, tablet, and desktop, with fast, secure calculations. Bookmark it for regular strength assessments. MultiCalculators.org provides a wide range of fitness and utility tools; explore our navigation above for more resources.

⚠️ Note: 1RM estimates are approximate. Individual factors like muscle fiber type, fatigue, and technique affect actual performance. Use this data to guide workouts, not as absolute truth. Always warm up thoroughly and consult a coach for maximal attempts. The tool supports both metric and imperial units — just input the weight you lifted in your preferred unit. The result unit matches your input (kg or lbs).