How to calculate your daily calorie needs

Why are calorie needs personal?

"2,000 calories a day" is a labeling standard, not your need. Your height, weight, age, sex and how much you move during the day determine the energy you burn. Two people can eat the same plate of food and one loses weight while the other gains it.

The good news: you don't need a lab to estimate this need with reasonable accuracy. A scientifically tested formula and an honest estimate of your activity are enough.

The calculation in four steps

1. Find your basal metabolic rate (BMR): the energy your body burns while fully at rest.
2. Multiply by an activity factor: the result is your total daily energy expenditure (TDEE).
3. Adjust for your goal: add a deficit to lose weight or a surplus to gain.
4. Split into macros: divide the calories between protein, carbohydrate and fat.

Step 1: Basal metabolic rate

BMR is the energy spent on breathing, keeping your heart beating and maintaining body temperature, and it is usually the largest part of daily expenditure. The most widely used estimation method today is the Mifflin-St Jeor equation.

The Mifflin-St Jeor equation

• Men: (10 × weight) + (6.25 × height) − (5 × age) + 5
• Women: (10 × weight) + (6.25 × height) − (5 × age) − 161
• Enter weight in kilograms, height in centimeters and age in years; the result is in kcal/day.

The formula works well for an average adult; the error can grow in very muscular people or in the obesity range. Treat the result as a starting point, not an exact value.

Step 2: Activity factor

Multiply your BMR by the factor that matches how much you move during the day. The most common mistake is choosing a higher activity level than the real one; if you're unsure, start one level lower.

• 1.2 — Sedentary: desk job, no regular 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 plus daily training

Step 3: Deficit or surplus for your goal

If you want to maintain your weight, eat at your TDEE. A deficit of about 300–500 kcal a day to lose weight, or a surplus of 200–300 kcal to build muscle, is a good starting point for most people. Bigger gaps look fast in the short term but are hard to sustain.

Worked example

Step 4: Macro ratios

Once your calorie target is set, you split it into macros. Protein and carbohydrate give 4 kcal per gram, fat gives 9 kcal. The table below shows four common splits and their gram equivalents on a 2,000 kcal day.

Swipe sideways to see the table →

Whichever ratio you choose, total calories are what mainly determine weight change. Pick the ratio based on how full it keeps you, your training and what you can stick to for a long time.

Safe limits

• Losing about 0.5–1% of your body weight per week is sustainable for most adults.
• Don't set your calorie target below your BMR without professional supervision.
• Keep protein high while losing weight (about 1.2–1.6 g/kg); it reduces muscle loss and keeps you full.
• Recalculate after every 4–5 kg of change; as your weight changes, so does your need.

When should you see a professional?

If you are pregnant or breastfeeding, have a chronic condition such as diabetes, kidney or thyroid disease, are under 18, or have had an eating disorder in the past, set your calorie target with a doctor or dietitian.

Sources

1. Mifflin MD, St Jeor ST et al. A new predictive equation for resting energy expenditure in healthy individuals. Am J Clin Nutr. 1990;51(2):241–247.
2. Frankenfield D, Roth-Yousey L, Compher C. Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults. J Am Diet Assoc. 2005;105(5):775–789.
3. Hall KD et al. Quantification of the effect of energy imbalance on bodyweight. Lancet. 2011;378(9793):826–837.
4. World Health Organization. Healthy diet fact sheet, 2020.

This content is for information only and is not medical advice. Last updated: October 5, 2026.