How the calorie targets are built
The calculator first estimates your basal metabolic rate (BMR) with the Mifflin–St Jeor equation, which uses your weight, height, age and sex. BMR is the energy your body would burn lying still all day.
It then multiplies BMR by an activity factor that reflects how much you move, giving your maintenance calories — the amount that keeps your weight roughly stable. Loss and gain targets are simply maintenance shifted down or up by a daily calorie amount.
What each target means
Maintenance is your baseline. Mild weight loss trims about 250 calories a day for a gentle, slow drop. Weight loss trims about 500 a day, a pace that corresponds to roughly half a kilogram per week for many people. Weight gain adds about 500 a day to support a steady increase.
The bar chart lines the four targets up side by side so you can see how far apart your loss and gain options sit from maintenance.
Using the numbers in practice
Treat these figures as a starting estimate and adjust based on what the scale actually does:
- Track your weight as a weekly average rather than reacting to daily swings.
- If weight is not moving after two to three weeks, nudge calories by 100 to 200 and reassess.
- Pair a deficit with adequate protein and resistance training to preserve muscle.
- Very low intakes are hard to sustain and rarely necessary for steady progress.
Health disclaimer
These estimates are for general guidance and are not medical or nutritional advice. Calorie needs vary widely between individuals, and aggressive deficits can be harmful. If you are pregnant, breastfeeding, under 18, have a medical condition, or a history of disordered eating, consult a doctor or registered dietitian before changing your intake.
Formula
maintenance = BMR · activity factorFrequently asked questions
- Why is a 500 cal deficit suggested for weight loss?
- A pound of fat stores roughly 3,500 calories, so a 500 cal/day deficit yields about one pound (0.45 kg) of loss per week — a sustainable pace for most people.