How many calories do I need to maintain my weight?

Your maintenance is the calories you burn, and it’s a range, not a single number. Start at the middle of the range a calculator gives you. Eat about the same each day for four weeks and weigh in most mornings. If the trend is flat, you’ve found it. If you’ve just lost weight, expect it to be lower than before: about 10 calories a day less for every pound you lost.

Your burn changes from day to day with your steps, and the formula behind any calculator is within 10% for about four people in five. So a calculator’s 2,400 may really be 2,200 or 2,600 for you.

The simple version

Think of a bathtub with the drain open. You can’t see how fast it drains. But if you keep the tap steady and the water level holds, the tap matches the drain.

Find yours in four weeks

• Log what you eat, every day, as well as you can.
• Weigh in most mornings, after the bathroom and before eating.
• Compare averages. Take the average of your first week and of your last.
• Do the math. Your maintenance is your average daily calories, plus 500 for each pound a week you lost, or minus 500 for each pound a week you gained. That’s the old rule of 3,500 calories a pound.

For example, you averaged 2,000 calories and lost half a pound a week. Your maintenance is about 2,250.

After weight loss

A smaller body costs less to run. In NIH scientists’ model of weight change, every 10 calories a day you cut for good takes off about a pound in the end. Turned around, each pound lost lowers your burn by about 10 calories a day, so 20 pounds lowers it by about 200. Dieting adds a small extra dip on top: in a 2020 study, 71 people who lost about 30 pounds burned about 90 calories a day less at rest than their new size explained, and about 40 after four weeks at a steady weight.

What to do

• Do the four weeks on the real TDEE calculator.
• Or let Gyroscope keep the count: photograph your meals, weigh in most mornings, and your steps come in from your phone or watch. Your weight trend gives a calorie-burn estimate, and your TDEE gets its own trend. See tracking it in Gyroscope.