BMR Calculator Formula

Understand the math behind the bmr calculator. Each variable explained with a worked example.

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Formulas Used

BMR (Calories/day)

bmr = 10 * weight_kg + 6.25 * height_cm - 5 * age + 5

Calories/hour at rest

bmr_per_hour = (10 * weight_kg + 6.25 * height_cm - 5 * age + 5) / 24

Variables

VariableDescriptionDefault
weight_lbsWeight(lbs)170
height_inches_totalHeight (total inches)(inches)70
ageAge(years)30
weight_kgDerived value= weight_lbs * 0.453592calculated
height_cmDerived value= height_inches_total * 2.54calculated

How It Works

What is BMR?

Basal Metabolic Rate is the number of calories your body needs to maintain basic life-sustaining functions while at complete rest.

Mifflin-St Jeor Formula (Male)

BMR = 10 x weight(kg) + 6.25 x height(cm) - 5 x age + 5

Worked Example

A 30-year-old, 170 lbs, 70 inches tall.

weight_lbs = 170height_inches_total = 70age = 30
  1. 01Weight: 77.1 kg, Height: 177.8 cm
  2. 02BMR = 10(77.1) + 6.25(177.8) - 5(30) + 5
  3. 03= 771 + 1,111.25 - 150 + 5 = 1,737 cal/day

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