How is BMR different from TDEE?

BMR is at complete rest. TDEE = BMR × activity multiplier and represents actual daily calories burned. TDEE is what you use for calorie targets.

Why Mifflin-St Jeor over Harris-Benedict?

Mifflin-St Jeor (1990) was developed on modern data and is around 5% more accurate than the original 1919 Harris-Benedict formula for most people.

Is the BMR calculator free?

Yes — free to use, with no signup, no limits and no personal details required. The site is supported by advertising rather than subscriptions.

Is my data saved or sent anywhere?

No. Every calculation runs in your browser, so the numbers you type are never transmitted to us or stored on a server. Closing the tab discards them.

Can I rely on this instead of seeing a professional?

No. These formulas give a useful reference point, but they cannot account for your medical history or body composition. Use the result to inform a conversation with a qualified professional, not to replace one.

Can I share or save my results?

Yes. Your inputs are stored in the page URL, so you can copy the link from the address bar (or use the share button) to bookmark a scenario or send it to someone else.

BMR Calculator

Basal Metabolic Rate — the calories your body needs to sustain vital functions at complete rest.

Your details

Sex

Age

yrs

Height

Weight

Basal metabolic rate

1,699 kcal / day

Calories burned at complete rest

How this is calculated

The Mifflin-St Jeor equation is currently the most accurate common formula for BMR:

Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161

BMR is the energy required to keep your organs running, maintain body temperature and replace cells while completely at rest. Add activity to get your Total Daily Energy Expenditure (TDEE) — see the calorie calculator.

Who this calculator is for

This is aimed at people tracking their own health who want a clear number to work from rather than a vague guideline. It is useful as a starting reference point when setting goals or reviewing progress, and as context for a conversation with a qualified professional.

Assumptions and accuracy

These are population-level formulas. They do not account for body composition, muscle mass, pregnancy, medical conditions, or medication, so an individual result can be some way off. This is general information, not medical advice — speak to a doctor or registered dietitian before acting on it.

Frequently asked questions

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See every calculator on the homepage, browse our free online tools, or read the guides on our blog.