What it calculates
Your daily calorie need is the energy your body uses at rest (BMR) plus the energy used in daily activity and exercise.
How it works
BMR is estimated with the Mifflin–St Jeor equation and multiplied by an activity factor. The goal adds or subtracts a fixed daily amount as a starting point.
Formula
Calories = BMR × activity factor ± goal adjustment
- Activity factors 1.2 (sedentary) to 1.9 (very active)
- Goal adjustment −500 to +500 kcal per day
How to use it
- Enter sex, age, height and weight.
- Choose your usual activity level honestly.
- Choose a goal and read your daily target.
For the defaults — a 30-year-old, 165 cm, 65 kg, lightly active —
Why it helps
- Gives a sensible starting point you can adjust from real results.
- Warns when a target falls below commonly advised minimum intake.
Limitations
- Equations can be off by 10% or more for individuals.
- Not suitable in pregnancy, for children or for medical conditions without professional advice.
Frequently asked questions
How quickly should I lose weight?
Gradual change is generally advised. A doctor or dietitian can set a pace that is safe for you.
Do you store what I enter?
No. This calculator runs entirely in your browser. Your measurements and dates are not sent to or stored on our servers.
Sources
- A new predictive equation for resting energy expenditure in healthy individuals — Mifflin MD, St Jeor ST, et al. American Journal of Clinical Nutrition, 1990 (checked 2026-09-27)
This calculator gives a general estimate only. It is not medical advice, a diagnosis or a treatment plan, and it does not replace a consultation with a doctor or registered dietitian. Your inputs stay in your browser and are not stored by UrbanFiling.