How many calories do you need each day? Our free calorie calculator estimates the energy your body uses based on your age, sex, height, weight and activity level. It then shows how many calories to eat to maintain, lose or gain weight at a safe, steady pace.
How this calorie calculator works
The calculator uses the Mifflin-St Jeor equation, which research has found to be one of the most accurate formulas for estimating calorie needs in healthy adults. It works in two steps:
- Basal metabolic rate (BMR): the calories your body burns at complete rest to keep you alive, for breathing, circulation and keeping your organs working.
- Men: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) + 5
- Women: BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age) − 161
- Total daily energy expenditure (TDEE): your BMR multiplied by an activity factor, from 1.2 for a mostly sitting lifestyle to 1.9 for very physical work plus training. This is roughly the number of calories you need to maintain your current weight.
Activity levels explained
| Activity level | Description | Factor |
|---|---|---|
| Sedentary | Desk job, little or no exercise | 1.2 |
| Lightly active | Light exercise 1 to 3 days a week | 1.375 |
| Moderately active | Moderate exercise 3 to 5 days a week | 1.55 |
| Very active | Hard exercise 6 to 7 days a week | 1.725 |
| Extra active | Physical job plus daily training | 1.9 |
Most people overestimate how active they are. If you are unsure, choose the lower option and adjust later.
Calories for weight loss
To lose weight, you need to eat fewer calories than your body uses. A daily deficit of about 500 calories leads to a loss of roughly 0.5 kg (1 lb) a week for many people, while a 250-calorie deficit leads to a slower, gentler loss. Health organisations generally recommend losing 0.5 to 1 kg (1 to 2 lb) per week as a safe and sustainable pace.
Very low-calorie diets can cause muscle loss, tiredness and nutrient deficiencies, and are hard to sustain. As a general rule, women should not go below about 1,200 calories a day and men below about 1,500 calories a day unless they are supervised by a doctor.
How accurate is the result?
Every calorie formula is an estimate. Your real needs can be 10% higher or lower because of genetics, muscle mass, hormones, sleep and medical conditions. The best way to use your result is as a starting point:
- Eat around your target for two to three weeks.
- Weigh yourself at the same time of day, a few times a week, and look at the average.
- If your weight is not moving in the direction you want, adjust by 100 to 200 calories and check again.
Tips for reaching your calorie goal
- Prioritise protein and fibre. They help you feel full on fewer calories. Good sources include eggs, yogurt, fish, chicken, beans, lentils, vegetables and whole grains.
- Watch liquid calories. Sugary drinks, juices and specialty coffees add up quickly. Water is the best everyday drink, and our Hydration Calculator can help you set a goal.
- Use smaller plates and check portion sizes, especially for oils, nuts, cheese and snacks.
- Stay active. Regular walking and strength training increase the calories you burn and help protect muscle while you lose fat.
- Sleep well. Short sleep is linked with increased hunger and cravings.
Want to check whether your current weight is in a healthy range? Try our BMI Calculator.
Frequently asked questions
What is the difference between BMR and TDEE?
BMR is the energy your body uses at complete rest. TDEE adds the energy you use for daily movement, exercise and digesting food. Your TDEE is the number to use for planning your meals.
Should I eat back the calories I burn during exercise?
Your activity level already includes your regular exercise, so you usually do not need to add more. Fitness trackers also tend to overestimate calories burned.
Why am I not losing weight on my calorie target?
Common reasons include underestimating portion sizes, forgetting drinks and snacks, overestimating activity, or normal water weight changes. Track carefully for two weeks before adjusting. If you still have concerns, talk to a doctor, as some medical conditions and medicines can affect weight.
Is this calculator suitable for teenagers or during pregnancy?
No. It is designed for healthy adults aged 18 and over. Children, teenagers, pregnant or breastfeeding women and people with medical conditions have different needs and should get personalised advice from a healthcare professional.
This calorie calculator is for general information only and is not a substitute for medical advice. Talk to your doctor or a registered dietitian before starting any weight-loss plan, especially if you have a health condition.
