Why is it slightly different from Mifflin?

The two equations use different constants. Mifflin tends to run a few percent higher for most adults. Either is fine for planning.

BMR (Harris-Benedict) Calculator

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Units

Weight

Height

Age

Sex

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The original Harris-Benedict formula, revised in 1984. Compare it to the Mifflin-St Jeor estimate to see the range.

How to use BMR (Harris-Benedict) Calculator

Open the toolNo signup and nothing to install; it works as soon as the page loads.
Set “Units”
Set “Weight”
Set “Height”
Set “Age”
Set “Sex”
Read the resultChange any input and the result is recalculated immediately.

Worked example with the defaults

BMR (HARRIS-BENEDICT) · Classic BMR formula: 1702

Nothing you enter leaves your device

All of the work happens inside your browser. Whatever you type is never packaged up and sent to a server, and no request this page makes carries it.

That makes it safe for contract amounts, personal details and internal documents you would rather not hand to a third party — close the tab and it is gone.

What this tool does not do

BMR (Harris-Benedict) Calculator only does what a browser can do on its own — it talks to no backend service. So it keeps no history for you and syncs nothing across devices; if you need a record, copy or download the result.

It is also not a substitute for professional judgement. For legal, medical or tax decisions, treat the output as a starting point rather than a final answer.

Frequently Asked Questions

Why is it slightly different from Mifflin?: The two equations use different constants. Mifflin tends to run a few percent higher for most adults. Either is fine for planning.