1RM Calculator – Calculate Your Maximum Strength Based on Weight Lifted and Reps
The 1RM calculator (One Rep Max) estimates your one-repetition maximum strength based on a test set. Enter the weight lifted and number of reps to get your estimated 1RM using multiple formulas.
The tool uses well-known formulas like Epley, Brzycki, and Lander. You'll also see training percentages (60-95% of 1RM) for different training goals — strength, hypertrophy, and endurance. Perfect for tracking progress at the gym.
How to use the 1RM calculator for training?
For example, in bench press: if you lift 175 lbs × 5 reps, your estimated 1RM is about 200 lbs. From this, you can calculate training weights: strength (85-95%, or 170-190 lbs), hypertrophy (67-85%, or 135-170 lbs), and endurance (under 67%, or under 135 lbs). Direct 1RM testing is riskier — estimation formulas are a safer alternative.
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Browse all tools →The 1RM calculator estimates your one-rep maximum strength (1RM) for different lifts. This tool is ideal for strength trainers who want to plan their workout programs safely without performing a heavy maximum test.
Enter the weight lifted and number of reps, and the calculator estimates your theoretical one-rep maximum using several different formulas.
- Enter weight (kg) and rep count – get an estimate of your 1RM.
- The calculator also shows percentages for different rep ranges to support training.
- You can use the result to plan weights and intensity for your training program.
The 1RM estimate is a mathematical calculation, not an exact measurement. The result is indicative and depends on the formula used.
- The estimate is most reliable when the rep count is 1-10.
- Different formulas (Epley, Brzycki, etc.) may give slightly different results.
- Don't replace an actual maximum test with just a calculator if precision is critical.
Maximum strength is affected by many factors, such as technique, alertness, and recovery.
- Don't attempt the weight given by the calculator without experience and a safe training environment.
- The calculator doesn't account for individual structural or health differences.
- If you're a beginner, seek guidance from an experienced coach before heavy lifts.