One Rep Max Calculator

You do not need to grind out a true max single to know your one rep max. Take a recent hard set, put the weight and reps in below, and this estimates your 1RM using the two most established formulas in strength training, then turns it into the percentage table you actually program from. I use the 5 rep estimate myself: heavy enough to be honest, light enough that form holds.

Units

Weight lifted (from a recent hard set, not a guess)

Reps completed (taken close to failure)

Estimated One Rep Max

114.5kg

Average of both formulas, from 100 kg x 5 reps

116.5 kg

Epley

112.5 kg

Brzycki

Training Percentages

% 1RMLoadTypical repsWhat it trains

95%109 kg1-2Max strength

90%103 kg3-4Max strength

85%97.5 kg5-6Strength

80%91.5 kg7-8Strength / hypertrophy

75%86 kg9-10Hypertrophy

70%80 kg11-12Hypertrophy

65%74.5 kg13-15Hypertrophy / endurance

60%69 kg15-18Muscular endurance

55%63 kg18-20Muscular endurance

50%57.5 kg20+Endurance / warm-ups

These are estimates, not promises

Both formulas are regression equations fitted to averages, and individuals vary. They are most accurate in the 2 to 6 rep range and the error grows as reps climb; above about 10 reps the estimate can drift well off your true max, because high rep sets test endurance as much as strength. Treat the number as a programming anchor, and never attempt a max single without a spotter or safety bars.

Pushing heavy singles at home?

A power rack with proper safety bars is non-negotiable for training near your max alone.

Read the Power Rack Guide