Rep Max Percentage Calculator

Work out rep max percentage instantly with clear inputs, formula shown and shareable results.

About Rep Max Percentage Calculator

Percentage-based programming sets the working weight as a share of one-rep max, and the Epley relation inverts to predict how many reps that load allows: reps = 30(1/percentage - 1). At 80% of a 140 kg max the bar carries 112 kg and should permit about seven or eight reps. Below 60% the prediction becomes unreliable because endurance rather than strength limits the set.

Formulas

Working weight

weight = 1RM x percentage

Reps from percentage (Epley)

reps = 30 x (1 / percentage - 1)

Worked example

With the default values below, Rep Max Percentage Calculator returns Working Weight of 112.0. Change any input above and every figure here is recalculated in your browser.

Inputs used

Your one-rep maxminimum 0 kg: 140 kg
Percentage of one-rep maxaccepts 10–110 %: 80 %

Results

Working Weight: 112.0 kg
Reps You Should Manage: 7.5
Plate Weight Per Side On A 20 kg Bar: 46.00 kg
Volume Load For Five Sets: 4,480 kg

Step by step

1Values used
2Working weight
3Reps from percentage (Epley)
4Working Weight= 112.0 kg
5Reps You Should Manage= 7.5
6Plate Weight Per Side On A 20 kg Bar= 46.00 kg
7Volume Load For Five Sets= 4,480 kg

Assumptions and limits

The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
This is an estimate from population-average equations, not a medical or diagnostic assessment. Individual results vary with genetics, training history and technique. Seek advice from a qualified coach or clinician before making significant changes to training.
This is an estimate for general information and not professional medical advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

This is an estimate from population-average equations, not a medical or diagnostic assessment. Individual results vary with genetics, training history and technique. Seek advice from a qualified coach or clinician before making significant changes to training.

Frequently Asked Questions

Why do published rep charts differ?

They use different formulas - Epley, Brzycki, Lombardi - which diverge above about eight reps. All are approximations of a very individual relationship.

Is 80% always seven reps?

No. Rep capacity at a given percentage varies with the lift and the athlete; squats typically allow more reps at 80% than deadlifts.