Calorie Deficit: How to Set One You Can Actually Keep
How to size a deficit against your own maintenance level, why the scale lies for a fortnight, and the signs you have cu…
Calorie Calculator
Work out daily calorie needs with the Mifflin-St Jeor equation, adjusted for activity level and your weight goal.
years
kg / lb
cm / in
Daily calories
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The formula
Mifflin-St Jeor: BMR = 10·weight(kg) + 6.25·height(cm) − 5·age + s, where s is +5 for men and −161 for women.
Every result on this page comes from this formula. Nothing is rounded until the final display, so figures match a spreadsheet to the cent.
How to use the Calorie Calculator
- Fill in each field with your own figures — the defaults are only there as an example.
- The result updates as you type, so there is no button to press.
- Check the breakdown under the main result for the supporting numbers.
- Use the copy button to take the result with you, or share the link to reload the same inputs.
Calorie Calculator — frequently asked questions
How big should a calorie deficit be?
A deficit of about 500 kcal per day produces roughly 0.5 kg (1 lb) of weight loss per week for most people. Deficits beyond 1000 kcal per day are hard to sustain and risk losing muscle.
Why do two people of the same weight need different calories?
Height, age, sex and lean mass all change basal metabolic rate, and daily activity can vary by more than 1000 kcal between a desk worker and a manual worker.
Is this calorie calculator free to use?
Yes. Every calculator on the site is free, needs no sign-up, and runs entirely in your browser, so your figures never leave your device.
How accurate is the result?
The maths is exact for the formula shown on the page. Accuracy in the real world depends on your inputs and on assumptions the formula cannot see, so treat the output as a well-grounded estimate rather than a quote.
Can I use it on my phone?
Yes. The page is responsive, weighs a few kilobytes and works offline once loaded, so it behaves the same on a phone as on a desktop.
Related reading
Focused versions of this calculator
Each of these does one specific job with its own defaults and explanation.
- Weight Loss Calorie Calculator Set a daily calorie target for weight loss based on your own maintenance level, with the …
- Bulking Calorie Calculator Set a calorie surplus for muscle gain, sized to add mass without unnecessary fat.
- Calorie Calculator in Pounds and Inches Work out daily calorie needs with the Mifflin-St Jeor equation, adjusted for activity lev…
- Calorie Calculator for Women Work out daily calorie needs with the Mifflin-St Jeor equation, adjusted for activity lev…
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About this calculator
Written and reviewed by The Samsung Calculator editorial team. Every calculator is written against a published formula, reviewed against at least one independent reference implementation, and dated when it changes.
Last reviewed August 15, 2026 · Calculation runs client-side · No data collected · Report an error