How Many Calories Do I Need per Day? BMR & TDEE Explained

Most adults need somewhere between 1,600 and 3,000 calories a day, but your own number depends on your sex, age, height, weight and activity. The most reliable quick method is to calculate your resting energy (BMR) with the Mifflin-St Jeor equation and multiply it by an activity factor to get your maintenance calories (TDEE). The Calorie Calculator does both instantly.

What are BMR and TDEE?

• BMR (basal metabolic rate) is what your body burns at complete rest: breathing, heartbeat, keeping warm.
• TDEE (total daily energy expenditure) is BMR plus everything you do: walking, working, exercising.

If you eat your TDEE, your weight stays about the same. Eat less and you lose weight; eat more and you gain.

How do I calculate my calories with Mifflin-St Jeor?

The equation (weight in kg, height in cm, age in years):

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

Then multiply by an activity factor:

Activity	Factor
Little or no exercise	1.2
Light: 1–3 days a week	1.375
Moderate: 3–5 days a week	1.55
Hard: 6–7 days a week	1.725
Very hard: physical job or training twice a day	1.9

Worked examples

A 30-year-old man, 180 cm, 80 kg, exercising 3–5 days a week:

1. BMR = 800 + 1,125 − 150 + 5 = 1,780 kcal
2. TDEE = 1,780 × 1.55 = about 2,760 kcal

A 30-year-old woman, 165 cm, 62 kg, exercising 1–3 days a week:

1. BMR = 620 + 1,031 − 150 − 161 = about 1,340 kcal
2. TDEE = 1,340 × 1.375 = about 1,840 kcal

The Calorie Calculator shows these two numbers plus a table of targets: lose 0.25 or 0.5 kg a week (250 or 500 kcal less), maintain, or gain 0.25 or 0.5 kg a week. In US units it shows the same targets in pounds.

How many calories should I eat to lose weight?

A deficit of about 500 kcal a day is a common starting point and usually gives around 0.5 kg (1 lb) of loss a week. A smaller deficit of 250 kcal is easier to stick to and protects muscle.

The calculator never suggests going below 1,200 kcal for women or 1,500 kcal for men. Eating less than that makes it hard to get enough protein, vitamins and minerals, and should only be done with a doctor.

For muscle gain, a small surplus of 250 kcal with enough protein and strength training limits fat gain. Our guide on calculating macros explains how to split those calories into protein, carbs and fat.

Why might my results be off?

• Activity level is guessed too high. Most people with desk jobs are "light" even if they go to the gym.
• Body composition. Very muscular people burn a little more than the formula predicts.
• Age and medical conditions. Thyroid problems and some medicines change energy needs.

The fix is simple: follow your target for two to three weeks, weigh yourself at the same time each morning and compare weekly averages. If nothing changes, move 100–200 kcal up or down.

What do 2,000 calories look like?

As a rough South Asian example: an omelette with 2 roti and chai with a little sugar for breakfast (about 450 kcal), daal, rice and sabzi for lunch (about 600), fruit and a handful of nuts as a snack (about 250), and chicken curry with 2 roti and salad for dinner (about 650). A Western version could be oats with milk and banana, a chicken salad wrap, yoghurt and fruit, and salmon with potatoes and vegetables.

To check a real day, paste it into the Food Calorie & Fiber Checker.

When to talk to a professional

Pregnant or breastfeeding women, teenagers, people with diabetes or kidney disease, and anyone with a history of eating disorders should get personal advice from a doctor or registered dietitian rather than relying on a calculator.

Find your number

Open the free Calorie Calculator, enter your details and pick the activity level that matches your normal week. It works in metric or US units and runs in your browser, so nothing you type leaves your device. Then check your weight against the healthy range with the BMI Calculator.