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BMR Calculator

Calculate your Basal Metabolic Rate using the Mifflin-St Jeor equation.

Last reviewed: 3 December 2025Source: NHS — Health A-Z
BMR Calculator · CAHealth & Lifestyle

Rates & sources

Population-average body composition metrics. Always consult a qualified clinician before making health decisions.

Source: NHS — Health A-Z — figures refreshed at the start of each tax year.

When to use this calculator

  • Before setting a new health goal or checking whether a plan is realistic.
  • When you want to compare different assumptions without tracking them manually.
  • When you need a quick baseline before discussing the result with a professional.

A realistic Canada planning example

Use these sample inputs as a quick scenario test, then change one variable at a time to compare outcomes.

Weight (kg)

80 kg

Height (cm)

178 cm

Age

35

Sex (1=Male, 0=Female)

1

After entering these figures, focus on bmr first and then rerun the tool with a more cautious assumption.

How to read your results

BMR

Use this metric to compare scenarios side by side and understand how the key drivers affect the final outcome.

Common mistakes

  • !Using optimistic assumptions without testing a more cautious scenario as well.
  • !Comparing outputs from different tools without checking that the inputs match.
  • !Treating the result as a final quote instead of a planning estimate.

What to do next

  • Try at least one more scenario so you can compare a realistic range instead of a single estimate.
  • Use the related calculators below to cross-check the decision from another angle.
  • Open one of the linked guides if you need more context before you act on the result.

Frequently asked

Basal Metabolic Rate is the number of calories your body uses at complete rest to maintain core functions like breathing, circulation, and cell production. It typically accounts for 60-70% of daily calorie burn in sedentary adults. BMR declines with age at roughly 1-2% per decade after 20, mostly due to lean-mass loss.

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