How Many Calories Should I Eat to Lose Weight?

The short version: most adults lose weight steadily on 15-25% fewer calories than they burn in a day. For a lot of people that lands somewhere between 1,500 and 2,300 calories.

But "a lot of people" is not you. The gap between a 55 kg office worker and a 95 kg scaffolder is close to a thousand calories a day, and following a number written for somebody else is the most common reason a diet either stalls or feels miserable.

Here is how to work out your own number in three steps, with the arithmetic written out so you can check every line.

Step 1: What your body burns doing nothing

Your BMR - basal metabolic rate - is the energy your body spends staying alive: heart, brain, breathing, temperature. It is roughly 60-70% of everything you burn, and it is the base of the whole calculation.

The formula used by almost every credible calculator, including ours, is Mifflin-St Jeor:

• Men: 10 x weight (kg) + 6.25 x height (cm) - 5 x age + 5
• Women: 10 x weight (kg) + 6.25 x height (cm) - 5 x age - 161

That is it. No metabolic testing, no genetics, no "slow metabolism" adjustment. If you would rather not do it by hand, the BMR calculator does it in both metric and imperial.

Step 2: Multiply by how much you actually move

Your TDEE - total daily energy expenditure - is your BMR times an activity multiplier:

• 1.2 - Sedentary: desk job, little or no exercise
• 1.375 - Lightly active: light exercise 1-3 days a week
• 1.55 - Moderately active: moderate exercise 3-5 days a week
• 1.725 - Very active: hard exercise 6-7 days a week
• 1.9 - Extra active: physical job, or training twice a day

Almost everybody picks one level too high. Three gym sessions a week on top of a desk job is lightly active, not moderately active. Forty minutes of lifting burns far less than most people assume, and an hour in the gym does not undo nine hours in a chair. If you are between two levels, take the lower one - you can always eat more later, and a target that turns out to be slightly low still produces results.

The TDEE calculator covers both steps at once.

Step 3: Subtract a deficit you can live with

A kilogram of body fat is worth roughly 7,700 calories (about 3,500 per pound). So a daily shortfall of 500 calories comes to 3,500 a week, or about 0.45 kg - the classic "one pound a week".

The better way to set it is as a percentage of your TDEE, because the same 500-calorie cut is trivial for someone burning 3,200 and brutal for someone burning 1,700:

• 10-15% below TDEE - slow and almost effortless. Ideal for the last 3-5 kg, or if you are training hard.
• 15-25% below TDEE - the sweet spot for most people. Visible progress, manageable hunger, muscle largely protected.
• More than 25% - fast, and the part nobody advertises: more muscle lost, worse energy, worse sleep, and a much higher chance of quitting in week three.

Skip the arithmetic entirely: the calorie deficit calculator runs all three steps and shows your target, your weekly rate, and a projected date for reaching your goal weight.

Worked example: 33-year-old woman, 72 kg, 168 cm, lightly active

• BMR: (10 x 72) + (6.25 x 168) - (5 x 33) - 161 = 720 + 1,050 - 165 - 161 = 1,444 calories
• TDEE: 1,444 x 1.375 = about 1,986 calories
• 20% deficit: 1,986 - 397 = about 1,590 calories a day
• Expected rate: 397 x 7 = 2,779 a week, or roughly 0.36 kg (0.8 lb) per week

A flat 500-calorie cut would put her at 1,486, close to the sensible floor for her size. The percentage approach gives her a hundred more calories a day and a rate she can hold for months.

Worked example: 38-year-old man, 95 kg, 182 cm, moderately active

• BMR: (10 x 95) + (6.25 x 182) - (5 x 38) + 5 = 950 + 1,137.5 - 190 + 5 = about 1,903 calories
• TDEE: 1,903 x 1.55 = about 2,950 calories
• 20% deficit: 2,950 - 590 = about 2,360 calories a day
• Expected rate: 590 x 7 = 4,130 a week, or roughly 0.54 kg (1.2 lb) per week

Same percentage, very different plate. He gets 770 more calories a day than she does and still loses faster, purely because he is bigger and moves more.

The floor you should not drop below

Very low intakes are not a shortcut. Below roughly 1,200 calories a day for women and 1,500 for men, it becomes difficult to hit your protein, fibre and micronutrient needs, hunger stops being manageable, and more of the weight you lose comes from muscle.

If your maths puts your target under that floor, do not eat less - move more and accept the slower rate. Anything below those numbers belongs under medical supervision, not in an app.

Your number is not permanent

A smaller body burns fewer calories. Lose 6-8 kg and the target that produced a steady loss becomes close to your new maintenance level, which is why almost every diet flattens out after a couple of months.

Recalculate every 4-5 kg, or whenever your rate of loss has been under half of what you planned for three weeks running. CalorTracker does this for you: your daily target is derived from the weekly rate you chose and your current weight, so it moves as you do. There is more on reading that signal in weight tracking that tells you whether your plan is working, and on breaking a genuine stall in overcoming diet plateaus.

What to put inside the number

Calories decide whether you lose weight. Macros decide how much of the loss is fat, and how you feel while it happens.

• Protein: 1.6-2.2 g per kg of body weight. The highest-return change you can make in a deficit - it protects muscle and it is the most filling of the three. Work yours out with the protein calculator.
• Fat: at least 0.6 g per kg. Hormones, vitamin absorption, and food that actually tastes of something.
• Carbohydrate: whatever is left. It is your training fuel, not the enemy.

The macro calculator splits your target for you.

The number is only half the job

Here is the uncomfortable part. Research into self-reported food intake keeps finding the same thing: people under-record what they eat, often by hundreds of calories, and they do it honestly. The olive oil in the pan, the handful from a colleague's desk, the second glass of wine, the "small" portion that was 180 g.

A perfect target logged badly beats nothing, but it loses to a rough target logged well. That is precisely why CalorTracker lets you photograph a plate instead of typing out six ingredients - the logging that gets done is the logging that takes five seconds. Snap the meal, let the AI identify the foods and estimate the portions, adjust anything that looks off, done.

Work out your number and start tracking free - the app calculates your target from your own body and goal, then keeps it honest as your weight changes.

Common questions

Do I eat back the calories I burn in the gym?

Only partly, and only if your activity multiplier did not already account for them. Fitness trackers and gym machines are famously generous with calorie burn. If you do eat exercise calories back, use about half of the reported figure.

Is 1,200 calories a day enough?

For most adult women it is a floor rather than a goal, and for most men it is too low. It is workable short term for a small, sedentary person, and a poor idea for anybody who trains. If your target lands there, add activity rather than removing food.

How quickly should I see it on the scale?

The first week often shows 1-2 kg, most of which is water and gut contents rather than fat. Then it slows to your real rate. Judge the plan on a four-week trend, never on one morning's number - normal daily fluctuation is bigger than a good day's fat loss.

Do I have to hit the number exactly every day?

No. Your body settles the account weekly, not daily. Being 200 over on Saturday and 200 under on Monday is a wash. Aim for a weekly average and stop treating a single meal as a failed diet.

What if I follow the number and still do not lose?

Three explanations cover almost every case, in order of likelihood: the logging is missing calories, the activity multiplier was too generous, or not enough time has passed to see through water-weight noise. Give it three consistent weeks of accurate logging before you change anything.

Ready to stop guessing? Get your personal target, then start logging by photo - it takes about five seconds a meal.