Measure consistently
Use a completed set with consistent range of motion and technique. Do not estimate from a warm-up set or a set stopped far from technical failure.
Multi-equation strength estimate
Compare seven one-rep-max equations from one submaximal set.
Use a near-technical-failure set to calculate a median, method range, formula spread and percentage-based training loads without treating the estimate as permission to attempt a maximal lift.
The calculation runs locally in this browser. Educational outputs do not replace professional assessment, diagnosis, treatment or emergency care.
Method and interpretation guide
Use the one-rep-max result as a transparent estimate
Use a completed set with consistent range of motion and technique. Do not estimate from a warm-up set or a set stopped far from technical failure. The worksheet exposes its assumptions so the result can be checked instead of accepted as a black box.
Read the assumptions
Each equation maps repetitions to an estimated maximal load differently. A near-technical-failure set of relatively low repetitions is more informative than a casual high-repetition set.
Escalate important decisions
A calculator cannot examine symptoms, medical history, medication effects or measurement quality. Use qualified professional guidance when the decision has health consequences.
Local calculation
Inputs are processed in this browser. No account or external calculator is required to produce the result.
False precision
Extra decimal places do not remove biological variation, input error or limits in the underlying population equation.
Scope
Each equation maps repetitions to an estimated maximal load differently. A near-technical-failure set of relatively low repetitions is more informative than a casual high-repetition set.
Simple by design
Three steps to a clearer number.
Enter your details
Use realistic values in each field. You can change them anytime.
Calculate instantly
The formula runs locally, so there is no account or waiting time.
Use the result
Treat the answer as a practical estimate for your next decision.