Calorie and deficit calculator
For adults 18 and older. Treat it as a starting estimate: your average weight over 2–3 weeks will tell you the real number.
How it works
Resting burn uses the Mifflin–St Jeor equation: 10 × weight (kg) + 6.25 × height (cm) − 5 × age, plus 5 for men or minus 161 for women.
That is multiplied by an activity factor: 1.2 for mostly sitting, 1.375 for some walking or 1–3 workouts a week, 1.55 for more movement. The result is maintenance.
A gentle deficit is 300–500 kcal below maintenance. The NHS suggests eating about 600 kcal a day less as a steady pace.
What it cannot know
For many people, actual burn differs from the formula by 10% or more. If your average weight has not moved in 2–3 weeks, take off 100–200 kcal; if you are losing faster than about 2 pounds a week or are always hungry, add some back.
These are estimates for adults, not a diagnosis. If you have a health condition, are pregnant, or take medication, go over the numbers with your doctor.
Read more
- counting calories without the obsession
- calorie deficit in plain language
- how much weight you can lose in a month
- BMI and waist calculator
- Steps to calories calculator