How to work out your maintenance calories
Your maintenance calories, sometimes called your TDEE (total daily energy expenditure), are made up of two parts. The first is your basal metabolic rate: the energy your body uses at complete rest to breathe, circulate blood and keep everything ticking over. The second is everything you do on top: walking, training, fidgeting, even digesting food.
The calculator above estimates your BMR with the Mifflin-St Jeor equation, then multiplies it by an activity factor. Someone at a desk all day multiplies by 1.2, while someone training hard six days a week multiplies by 1.725 or more. That is why two people of the same size can have maintenance figures hundreds of calories apart.
What to do with the number
Treat your result as a well-informed starting point rather than a fixed truth. Eat close to it for two or three weeks while tracking your weight a few mornings a week. If the trend is flat, you have found your maintenance. If it drifts up or down, adjust your intake by 100 to 200 kcal and watch again.
From there, the targets above give you a sensible deficit for fat loss or a modest surplus for building muscle. The smaller the change, the easier it is to sustain, and sustainability beats speed almost every time.
