How to use the calorie calculator
- Select your sex and enter your age.
- Enter your height and weight in metric or US units.
- Choose the activity level that best matches a typical week.
- Read your maintenance calories and the targets for gradual weight loss or gain.
Formula
How many calories do you need?
Your daily calorie needs depend on how much energy your body burns at rest and how active you are. This calculator uses the Mifflin–St Jeor equation, which research has repeatedly found to be the most reliable everyday BMR formula for adults, and multiplies it by a standard activity factor.
The calculation
Step 1: basal metabolic rate (BMR).
- Men:
10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5 - Women:
10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
Step 2: multiply by your activity factor.
| Activity level | Factor |
|---|---|
| Sedentary (little or no exercise) | 1.2 |
| Lightly active (1–3 days/week) | 1.375 |
| Moderately active (3–5 days/week) | 1.55 |
| Very active (6–7 days/week) | 1.725 |
| Extra active (physical job or 2× training) | 1.9 |
Worked example
A 30-year-old man, 178 cm, 75 kg, moderately active:
BMR = 750 + 1,112.5 − 150 + 5 = 1,717.5 kcal Maintenance = 1,717.5 × 1.55 = ≈ 2,662 kcal/day
To lose about 0.5 kg a week he’d aim for roughly 2,110 kcal/day; to gain lean mass slowly, about 2,940 kcal/day.
Weight loss and gain targets
The calculator shows four targets around your maintenance figure:
- Mild loss (−275 kcal), about 0.25 kg per week
- Loss (−550 kcal), about 0.5 kg per week
- Mild gain (+275 kcal), about 0.25 kg per week
- Gain (+550 kcal), about 0.5 kg per week
These use the common approximation that 1 kg of body fat stores about 7,700 kcal. Real-world results slow down as your body adapts, so re-calculate after every few kilograms of change.
Make the estimate work for you
- Eat at the target for two to three weeks and weigh yourself at the same time each morning.
- Compare the weekly average with the week before. Daily numbers swing with water.
- Adjust intake by 100–200 kcal if progress is faster or slower than planned.
Pair this with the BMI calculator to see where your weight sits relative to the healthy range for your height. This tool is for information only. Speak to a healthcare professional before major dietary changes, especially if you are pregnant, under 18 or managing a medical condition.
Frequently asked questions
What is BMR?
Basal metabolic rate is the energy your body uses at complete rest to keep you alive — breathing, circulation, cell repair. It typically accounts for 60–70% of the calories you burn each day.
What is TDEE?
Total daily energy expenditure is your BMR multiplied by an activity factor. It estimates the calories you burn on a typical day, which is the amount that keeps your weight stable.
How many calories should I cut to lose weight?
A deficit of about 500–550 kcal per day leads to roughly 0.5 kg (1 lb) of loss per week for most people. Larger deficits are harder to sustain and can cost muscle.
Is the calorie result exact?
No. Mifflin–St Jeor is among the most accurate prediction equations, but individuals can differ by 10% or more. Track your weight for 2–3 weeks and adjust.
Which activity level should I pick?
Choose based on a typical week, not your best week. Most people with desk jobs who exercise 3–4 times a week fit "moderately active" or slightly below.