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Health

BMR Calculator

Estimate your basal metabolic rate — the calories your body burns at complete rest.

Result

—

Fill in the inputs to see your result.

Inputs

yrs
cm
kg

Try an example

How it works

BMR is the energy your body needs just to keep your heart, lungs, brain, and organs running. Your real daily need is higher — multiply by an activity factor.

Formula

Mifflin–St Jeor: BMR = 10·kg + 6.25·cm − 5·age + (5 if male, −161 if female)

Common mistakes

  • Confusing BMR with TDEE — TDEE includes activity.
  • Using outdated Harris–Benedict numbers; Mifflin–St Jeor is more accurate.

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Last updated

Reviewed Apr 15, 2026.

Calcxo gives you the answer plus the reasoning behind it.

How this calculator works

Methodology, assumptions & limitations

BMR Calculator runs entirely in your browser. It applies the standard formula for this calculation to the values you enter and updates the result as you type — nothing is sent to a server, and no inputs are stored.

Assumptions

  • Inputs are entered in the units shown next to each field.
  • Values are treated as exact; the calculator does not round inputs before computing.
  • Results assume the standard, widely-used formula for this type of calculation.

Limitations

  • Real-world fees, taxes, regional rules, or special cases are not modelled unless explicitly listed.
  • The result is for general information and planning — it is not professional advice.
  • When precision matters (legal, medical, financial decisions), confirm with a qualified professional or an authoritative source.

Calcxo provides general-purpose calculators for information and planning. Results are not professional financial, medical, legal, or tax advice. See our disclaimer and sources & methodology for more.

Quick answer

BMR Calculator: in one paragraph

Estimate your basal metabolic rate — the calories your body burns at complete rest.

What this calculator does

BMR Calculator takes the values you enter and returns the result instantly in your browser. Estimate your basal metabolic rate — the calories your body burns at complete rest.

Why people use it

  • Get an answer in seconds without spreadsheets or manual math.
  • Try several scenarios side by side by tweaking the inputs.
  • Share or revisit the page later — nothing you type is stored.
  • Pair it with the related tools below to cross-check your numbers.

How to use the BMR Calculator

A concrete walkthrough you can follow line by line.

Open the BMR Calculator above, fill in each field with a real value, and the result updates as you type.

  1. 1. Fill in the required fields

    Every field labelled without 'optional' needs a value. Hints under each label explain the expected unit.

  2. 2. Read the headline result

    The big number at the top is the primary answer. The caption underneath translates it into plain English.

  3. 3. Check the breakdown

    Smaller rows show the inputs and intermediate steps the calculator used, so you can verify the math.

  4. 4. Try a different scenario

    Adjust any field and the result recalculates instantly — no need to reload.

Result

You'll have an answer plus the breakdown of how it was computed, ready to compare or share.

When to use this calculator

  • You need a quick, reliable bmr calculator answer.
  • You want to compare a few what-if scenarios before making a decision.
  • You're sanity-checking a number you got from somewhere else.
  • Use a more specialised calculator from the related list when your case has extra inputs (taxes, fees, schedules) this one doesn't model.

Common mistakes

  • Confusing BMR with TDEE — TDEE includes activity.
  • Using outdated Harris–Benedict numbers; Mifflin–St Jeor is more accurate.

Related calculators