How Many Calories Should I Eat to Lose Weight?

By HSP · Published October 5, 2026 · 5 min read · Health & Fitness

Weight loss comes down to taking in less energy than your body uses over time, but the right number of calories is personal. It depends on your size, age, sex, muscle mass and how active you are. Rather than picking a number from a diet plan, you can estimate your own starting point in a few minutes and then fine-tune it with real-world results. This article is general information; if you have a medical condition, are pregnant, are under 18 or have a history of eating disorders, talk to a doctor or registered dietitian before changing your diet.

Step 1: Estimate your basal metabolic rate (BMR)

Your BMR is the energy your body uses at rest to breathe, circulate blood and keep you warm. A widely used formula is the Mifflin–St Jeor equation:

• Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
• Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161

Example: a 35-year-old woman who is 165 cm tall and weighs 70 kg has a BMR of 10 × 70 + 6.25 × 165 − 5 × 35 − 161 ≈ 1,395 kcal a day.

Step 2: Multiply by an activity factor to get TDEE

Your total daily energy expenditure (TDEE) adds the calories you burn moving, exercising and digesting food. Calculators multiply BMR by a factor such as:

For the woman above with light activity: 1,395 × 1.375 ≈ 1,918 kcal a day. That is her estimated maintenance level: eating about this much should keep her weight roughly stable. The calorie calculator does both steps for you and shows targets for weight loss, maintenance and gain.

Most people overestimate how active they are. If you are unsure, pick the lower level; you can always adjust later.

Step 3: Choose a moderate calorie deficit

To lose weight, eat less than your TDEE. A common approach is a deficit of around 500 calories a day, which for many people leads to gradual loss. For the example above, that would mean roughly 1,400 to 1,450 kcal a day.

The old rule that every 3,500-calorie deficit equals one pound of fat is a simplification. As you lose weight, your body needs less energy, so progress slows over time even if you keep eating the same amount. The U.S. National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) offers a free Body Weight Planner that models this change and estimates how many calories you need to reach a goal weight by a certain date.

Very low intakes are hard to sustain, can make it difficult to get enough nutrients, and can cause muscle loss. Calculators commonly warn against going below about 1,200 kcal a day without medical supervision, and slower loss is generally easier to keep off.

Step 4: Track, then adjust

Formulas are estimates; individual metabolism varies. The most reliable way to find your number is to test it:

1. Eat at your target for two to three weeks.
2. Weigh yourself under the same conditions, for example first thing in the morning, several times a week, and look at the weekly average rather than daily swings.
3. If the average is not moving, reduce by 100 to 200 kcal a day or increase activity. If you are losing faster than planned or feel exhausted, eat a little more.

Daily weight changes are mostly water, salt and food in your gut, not fat. Trends over weeks are what count.

What to eat within your calorie target

The number matters, but so does what makes it up:

• Protein (beans, lentils, fish, eggs, lean meat, dairy) helps you feel full and protects muscle while losing weight.
• Vegetables, fruit and whole grains add fibre and volume for relatively few calories.
• Watch liquid calories such as sugary drinks, alcohol and large coffee drinks; they add up quickly. Water is a good swap; the water intake calculator estimates how much you need, and our guide explains how much water to drink a day.
• Plan for flexibility. An approach you can stick to for months beats a strict plan you abandon after a week.

Don’t forget activity and muscle

Exercise burns extra calories and, especially strength training, helps you keep muscle while you lose fat. Because muscle is denser than fat, the scale may move slowly even when your body is changing. Tracking your waist measurement or body fat percentage gives a fuller picture; see how to measure body fat at home and the body fat calculator.

Is your goal weight realistic?

BMI is a quick screening tool for whether weight is in a typical range for your height, although it does not account for muscle. Check yours with the BMI calculator and read BMI explained for its limits. Health benefits can start with a modest amount of weight loss, so you do not need to reach a “perfect” number to improve your health.

Quick recap

1. Estimate BMR with Mifflin–St Jeor.
2. Multiply by an honest activity factor to get TDEE.
3. Subtract a moderate deficit, often around 500 kcal a day.
4. Track for two to three weeks and adjust by 100 to 200 kcal.

For a deeper look at BMR, TDEE and the activity multipliers, read calories and TDEE explained.