BMR Calculator
Find your Basal Metabolic Rate and daily calorie needs by activity level.
TL;DR — BMR Calculator: A Basal Metabolic Rate (BMR) calculator estimates the calories your body burns at complete rest — the energy required to keep organs running. Cal44 uses the Mifflin-St Jeor equation, the most accurate of the common BMR formulas. Multiplying BMR by an activity factor gives Total Daily Energy Expenditure (TDEE).
What is the BMR Calculator?
A Basal Metabolic Rate (BMR) calculator estimates the calories your body burns at complete rest — the energy required to keep organs running. Cal44 uses the Mifflin-St Jeor equation, the most accurate of the common BMR formulas. Multiplying BMR by an activity factor gives Total Daily Energy Expenditure (TDEE).
How to use the BMR Calculator
- Enter age, sex, weight and height.
- Select your activity level (sedentary, light, moderate, active, very active).
- Read your BMR (resting calories) and TDEE (total daily calories).
Formula
Men: BMR = 10·W + 6.25·H − 5·A + 5 Women: BMR = 10·W + 6.25·H − 5·A − 161
W = weight (kg) · H = height (cm) · A = age (years) · Activity multipliers — Sedentary 1.2 · Light 1.375 · Moderate 1.55 · Active 1.725 · Very Active 1.9
Worked example
A 30-year-old woman, 65 kg, 168 cm tall. BMR = 10·65 + 6.25·168 − 5·30 − 161 = 1,389 kcal. Lightly active TDEE = 1,389 × 1.375 ≈ 1,910 kcal/day.
Frequently asked questions
What's the difference between BMR and TDEE?
BMR is calories burned at rest. TDEE is BMR multiplied by an activity factor to include movement, exercise and digestion.
Why Mifflin-St Jeor over Harris-Benedict?
Mifflin-St Jeor (1990) is more accurate for modern populations and is the formula most clinical dieticians use. Harris-Benedict (1919, revised 1984) tends to overestimate BMR by 5–10%.
How accurate is the BMR estimate?
Within about ±10% for most adults. For competitive athletes or those with significant body composition extremes, a metabolic test (indirect calorimetry) is more accurate.
Does BMR decrease with age?
Yes — typically by about 1–2% per decade after age 20, mainly due to muscle loss. Strength training mitigates the decline.
How do I lose weight using BMR?
Eat below TDEE. A deficit of 500 kcal/day produces roughly 0.5 kg of fat loss per week. Cal44's Calorie Calculator computes the target for you.