How it works
The calculator supports Epley, Brzycki, Lombardi, Lander, Mayhew, O’Conner, and Wathan. “Average” reports the mean of all valid estimates.
Input query strings and outputs
Use an input name in this page’s URL as ?name=value, and join additional inputs with &. Portable shared links may instead use the compact ?ac= state parameter.
Input query strings
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?unitSystem=Weight unitsChoice · Required · Default: lb · Accepted values: lb, kg
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?liftedWeight=Weight liftedNumber · Required · Default: 135
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?repetitions=Repetitions completedNumber · Required · Default: 5
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?formula=FormulaChoice · Required · Default: average · Accepted values: average, epley, brzycki, lombardi, lander, mayhew, oconner, wathan
Outputs
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oneRepMaxEstimated one-rep maxNumber · Primary output
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epleyEpley estimateNumber
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brzyckiBrzycki estimateNumber
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formulaSpreadFormula rangeText
Training table
The percentage table is a load-planning reference. It does not assess readiness, technique, fatigue, or injury risk.