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BMR Calculator

Updated August 2026 Last reviewed 10 August 2026 Health & Lifestyle NHS: healthy weight tools

Your BMR is the energy your body burns at complete rest just to stay alive — breathing, heartbeat, temperature control. It is usually 60–70% of your total daily calorie burn.

Enter your details to get your BMR. Multiply it by an activity factor (see the calorie calculator) for your full daily needs.

Your details

Results

BMR (calories at rest)
1780 kcal/day
BMR per hour
74.2 kcal
BMR per week
12460 kcal

How the calculation works

We believe numbers should be transparent. Here is the formula behind this calculator.

BMR = 10×kg + 6.25×cm − 5×age (+5 male / −161 female)

Worked example

Worked example: 80 kg, 180 cm, 30, male

BMR = 10×80 + 6.25×180 − 5×30 + 5 = 1,780 kcal/day.
That is about 74 kcal an hour at rest.
Add an activity factor to this to estimate total daily burn.

Important assumptions

  • Uses the Mifflin-St Jeor equation, widely used by dietitians.
  • BMR falls slightly with age and is affected by muscle mass.
  • This is an estimate, not a medical measurement.

Rates & official sources

Every calculation is based on the official rates and rules published by GOV.UK and HMRC.

NHS: healthy weight tools nhs.uk

Frequently asked questions

What is the difference between BMR and TDEE?

BMR is your burn at complete rest. Total daily energy expenditure (TDEE) adds your activity on top. Multiply your BMR by 1.2 (sedentary) to 1.9 (very active) to get TDEE.

Why does BMR change with age?

Muscle mass usually declines with age, and muscle burns more calories than fat at rest. Keeping or building muscle through strength training raises your BMR.

Is a low BMR a problem?

Not by itself — smaller people naturally have lower BMRs. If you are losing weight easily, your BMR plus activity may just be high; use the calorie calculator for your full needs.

Related calculators

Calorie Calculator

Estimate your daily calorie needs from your BMR and activity level.

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BMI Calculator

Work out your Body Mass Index, your weight category and the healthy weight range for your height.

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Water Intake Calculator

Estimate your daily water intake target from your weight and activity.

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These calculations are estimates for guidance only and are not professional financial, tax or legal advice. UK rates and rules change, so always verify important figures with official GOV.UK / HMRC information or speak to a qualified professional. See our full disclaimer.