1RM Strength Calculator

Predict your true one rep max with science backed equations adjust for RPE convert units and auto round to plates build warmup sets see training zones and accessory guidance get printable results shareable links and mobile friendly interface for athletes coaches and lifters seeking precise progress tracking with history table advanced options and export

Advanced
Estimate one-rep max with multiple formulas RPE and rounding
Enter the weight you lifted for the given reps.
1 to 20 reps supported. Very high reps reduce accuracy.
Heuristic adjusts for reps in reserve. Choose 10 if all-out.
kg
Use 2.5 for kg plates or 5 for lb plates. Zero for no rounding.
Common steps are 5 or 2.5.
FAQs
Multiple methods are shown because accuracy varies by lift training age movement pattern and repetition range. Use the robust average and your own history to calibrate.
RPE accounts for reps in reserve. Lower RPE increases the effective rep count slightly which raises the 1RM estimate to reflect submax effort.
Pick the unit you load on the bar. All math runs internally in kilograms then converts back to your selection so results match your plates.
Use 2.5 for typical kilogram plates and 5 for pound plates. Set zero if microloading or if you prefer exact numbers without plate rounding.
Yes. Bench press often aligns with Mayhew or Wathan while squat and deadlift can favor Epley or O’Conner. Compare methods and use your log to decide.
Formulas are most reliable between 1 and 12 reps. Beyond that error grows. Consider testing a heavy triple or single and recalculating for better precision.

Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.