Daily calorie calculator
Health & fitnessHow many calories do you need a day?
Your resting energy (BMR) and an estimate of the energy you use in a day, in kcal or kJ, from your age, size and activity.
About you
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Daily energy need
2,133 kcal
Resting energy (BMR) 1,376 kcal, times an activity factor of 1.55.
From resting energy to daily need
- Resting energy (BMR)
- 1,376 kcal
- Activity factor
- 1.55
- Range for this activity level
- 1,927 kcal to 2,326 kcal
- Daily need in kilojoules
- 8,925 kJ
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Daily need by activity level
The same person at each activity level. Your level is marked.
| Activity level | Activity factor | Energy per day |
|---|---|---|
| Light: mostly seated or on your feet, little exercise | 1.40 to 1.69 | 2,133 kcal |
| Moderate: on your feet much of the day, or regular exercise | 1.70 to 1.99 | 2,546 kcal |
| Vigorous: hard physical work or daily intense training | 2.00 to 2.40 | 3,028 kcal |
What this estimate cannot tell you
- This is an estimate for a typical person. Real needs differ with body composition, genes, health and how active you really are.
- It is meant for healthy adults. It does not apply to children, to pregnancy or breastfeeding, or to people with a medical condition.
- It does not tell you how much to eat to lose or gain weight. A health professional can help with that.
Your resting energy (BMR) and an estimate of the energy you use in a day, in kcal or kJ, from your age, size and activity.
How to use
- Choose your sex, enter your age, height and weight, in cm and kg or in ft, in and lb.
- Pick the activity level that fits your usual week.
- Read your resting energy (BMR) and your estimated daily energy need, in kcal or kJ.
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How it works
Your body uses energy all day, even at rest, to keep you warm and your organs working. That resting energy is called the basal metabolic rate (BMR). On top of it comes the energy you spend moving, so your daily need is your BMR times a number that grows with how active you are.
BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years), then + 5 for men or − 161 for women (the Mifflin–St Jeor equation, fitted on measurements of 498 healthy adults). The daily need is BMR × an activity factor. We use 1.55 for a light lifestyle, 1.85 for a moderately active one and 2.2 for a vigorous one, the middle of the ranges set by FAO, WHO and the UN University. For example, a 35-year-old woman of 170 cm and 65 kg has a BMR of 1,377 kcal and, with light activity, needs about 2,134 kcal a day. One kilocalorie is 4.184 kilojoules.
It is an estimate, not a measurement. People of the same size can differ, and the equation was built from adults aged 19 to 78 who were healthy. It does not tell you how much to eat to lose or gain weight, and it is not for children, pregnancy, breastfeeding or illness.
Worked example
How is daily energy estimated from resting energy?
- For a man aged 30, weighing 80 kg and 180 cm tall, resting energy is about 1,780 kcal per day.
- The light-activity factor is 1.55.
Estimated daily energy: 1,780 × 1.55 = 2,759 kcal.
Frequently asked questions
What is the difference between BMR and daily calories?
BMR is the energy your body uses at complete rest. Your daily need is higher, because it adds the energy of everything you do, from walking to training.
Which activity level should I choose?
Think of a typical week, not your best one. If you mostly sit or stand and exercise a little, choose light. If you are on your feet most of the day or train regularly, choose moderate. Vigorous is for hard physical work or daily intense training.
Is a calorie the same as a kilocalorie?
On food labels and in everyday talk, yes: "calories" means kilocalories (kcal). In science a calorie is a thousand times smaller. Kilojoules (kJ) are the metric unit: 1 kcal is 4.184 kJ.
How many calories should I eat to lose weight?
A common starting point is 250 to 500 kcal a day below your daily need, and not below your BMR without medical advice. Weigh yourself for two to three weeks and adjust, because the formula is only an estimate.
Does switching from kcal to kJ change my energy needs?
No. It only changes the unit used to display the same energy estimate.
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