Testing your actual one-rep max in the gym carries real injury risk, especially for lifts like the squat, bench press, or deadlift. Our one-rep max calculator estimates your 1RM using a weight and rep count you can already lift safely, applying standard strength formulas to project what you could likely lift for a single rep.
This estimate is most accurate in the 2-10 rep range — sets with very high rep counts tend to produce less reliable 1RM estimates, since endurance starts to factor in more than pure strength. Most lifters use their estimated 1RM to program training percentages, like lifting at 80% of 1RM for strength work or 60% for higher-volume hypertrophy training.
If you’re training toward a specific strength or physique goal, pairing your 1RM numbers with proper nutrition matters just as much as the programming — our macro calculator and calorie (TDEE) calculator can help you dial in the nutrition side of your training.