Compare calculators

Both calculators run independently — change the inputs on either side to compare results.

One Rep Max Calculator

Predict your one-rep max (1RM) — the heaviest weight you could lift for a single perfect rep — from a recent set you actually performed. Used by powerlifters, strength coaches, and bodybuilders to prescribe percentage-based training (e.g., "work up to 5×5 at 80% of 1RM") without the risk and recovery cost of repeatedly testing true maxes.

Weight Lifted (kg)

Reps Performed (reps)

Calculation Formula

Training Experience

Fill in the required fields to see your result.

Fitness

VO2 Max Calculator

Estimate your VO2 max — the maximum rate at which your body can take up and use oxygen during exhaustive exercise — from a recent race time without needing a lab treadmill or metabolic cart. VO2 max is the single best whole-system measure of aerobic fitness and is strongly predictive of all-cause mortality.

Race Distance

Race Time (minutes) (minutes)

Age (years)

Body Weight (kg)

Fill in the required fields to see your result.

Key differences

	One Rep Max Calculator	VO2 Max Calculator
Category	Fitness	Fitness
Inputs required	4	4
Result	Estimated 1RM (kg)	Estimated VO2 Max (ml/kg/min)
What it does	Predict your one-rep max (1RM) — the heaviest weight you could lift for a single perfect rep — from a recent set you actually performed. Used by powerlifters, strength coaches, and bodybuilders to prescribe percentage-based training (e.g., "work up to 5×5 at 80% of 1RM") without the risk and recovery cost of repeatedly testing true maxes.	Estimate your VO2 max — the maximum rate at which your body can take up and use oxygen during exhaustive exercise — from a recent race time without needing a lab treadmill or metabolic cart. VO2 max is the single best whole-system measure of aerobic fitness and is strongly predictive of all-cause mortality.