Calorie Deficit Calculator — FAQ

A calorie deficit means your body uses more energy over time than it takes in from food and drink. It's a general concept in energy balance, not a specific diet.

It estimates your maintenance calories from your height, weight, age, sex, and activity level, then explains what a deficit means relative to that maintenance level and how energy balance works, so you understand the concept rather than just chasing a number.

No — and that's intentional. This is an educational tool that helps you understand the concept and see your estimated maintenance calories. It doesn't prescribe a specific intake. Individual calorie targets should be set with a doctor or registered dietitian.

Maintenance calories are the approximate energy your body uses in a typical day to stay at your current weight. They're estimated from your BMR (Basal Metabolic Rate) and activity level.

Because very large or very low calorie intakes can be unsafe and are not advisable without medical supervision. Gradual, sustainable changes are widely regarded as healthier and more effective long term.

Yes. You can enter your details in metric (cm, kg) or imperial (ft/in, lb), and the maintenance estimate updates instantly.

It's a well-established estimate, not an exact measurement. Real energy needs vary with body composition, genetics, health, and daily activity, so treat the figure as a general guide.

No. Your details are processed directly in your browser and are never stored or sent to a server, keeping your information completely private.

Yes, the tool is fully responsive and works on smartphones, tablets, and desktops without any installation.

A doctor or a registered dietitian. They can account for your full health picture and give safe, personalised guidance — something no online calculator can do. If you ever find yourself preoccupied with restricting food or with your weight, consider reaching out to a qualified professional for support.