How This Calculator Works

This calculator estimates your one-repetition maximum (1RM), which is the maximum amount of weight you can lift for a single repetition of a given exercise. Instead of testing a true max—which can be demanding and increase injury risk—this tool uses proven formulas to estimate your strength safely.

The calculation is based on the weight you lifted and the number of repetitions you performed. Multiple established formulas are used and averaged to improve accuracy across different rep ranges.

Step 1: Input Weight and Repetitions

Step 2: Apply 1RM Formulas

Step 3: Average the Results

Averaging multiple formulas helps reduce individual bias and provides a more balanced and reliable estimate of your true one-rep max.

Important Notes

• Best accuracy is achieved with 1–5 repetitions
• Estimates become less reliable above 10 repetitions
• Results are most consistent for compound lifts such as bench press, squat, deadlift, and overhead press
• Machine-based exercises like leg press may vary depending on equipment

Disclaimer:
This 1RM calculator provides an estimate based on standardized formulas and user inputs. Actual strength may vary depending on technique, fatigue, training experience, and equipment used. This tool is for informational purposes only and should not be considered medical or fitness advice. Always use proper form and caution when attempting maximal lifts.