How to use the Calorie Calculator (Daily Calorie Needs)
- Choose your sex and enter your age.
- Choose metric or US units, then enter your height and weight.
- Pick the activity level that best describes your week.
- Read your maintenance calories, BMR and the figures for losing or gaining weight.
Formula used
Mifflin-St Jeor: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 (men) or − 161 (women). Maintenance = BMR × activity factor. About 500 kcal a day more or less changes weight by roughly 0.5 kg (1 lb) a week.
Worked example
Here is the Calorie Calculator (Daily Calorie Needs) worked through with the example values shown above, so you can check each step by hand.
| Inputs | |
|---|---|
| Sex | Male |
| Age | 30 years |
| Units | Metric (cm, kg) |
| Height (cm or inches) | 175 |
| Weight (kg or pounds) | 75 |
| Activity level | Moderate (exercise 3 to 5 days a week) |
| Result | |
| Calories to maintain weight | 2,633 |
| Basal metabolic rate (BMR) | 1,699 |
| To lose about 0.5 kg (1 lb) a week | 2,133 |
| To gain about 0.5 kg (1 lb) a week | 3,133 |
| Note | These are estimates. Adjust after tracking your weight for a few weeks. |
Maintenance calories by activity level
For the default profile: a 30-year-old man, 175 cm, 75 kg.
| Activity level | Calories to maintain weight |
|---|---|
| 1.2 | 2,039 |
| 1.375 | 2,336 |
| 1.55 | 2,633 |
| 1.725 | 2,930 |
| 1.9 | 3,228 |
How the estimate is made
The Mifflin-St Jeor equation estimates the calories your body burns at rest: BMR = 10 × weight in kg + 6.25 × height in cm − 5 × age + 5 for men, or − 161 for women. For a 30-year-old man who is 175 cm and 75 kg, BMR = 750 + 1,093.75 − 150 + 5 = 1,699 calories a day.
That is multiplied by an activity factor: 1.2 for little or no exercise, 1.375 for light exercise, 1.55 for moderate exercise, 1.725 for hard daily exercise and 1.9 for very hard exercise or a physical job. At 1.55, maintenance is about 2,633 calories. A 30-year-old woman who is 165 cm and 62 kg with light activity gets a BMR of 1,340 and maintenance of 1,843.
The effect of activity
The activity level changes the answer a lot. For the man above, maintenance is 2,039 calories if sedentary, 2,336 with light activity, 2,633 with moderate activity, 2,930 when active and 3,228 when very active.
People often overestimate their activity, so if you are between two levels, choose the lower one and adjust after a few weeks of real results.
Losing or gaining weight
About 3,500 calories equal a pound of body fat (7,700 per kg), so eating 500 calories a day below maintenance leads to a loss of roughly 0.5 kg (1 lb) a week, and 500 above leads to a similar gain. For the man above that is 2,133 calories to lose and 3,133 to gain.
These are averages. The body adapts, water weight moves, and results vary, so use the figure as a starting point and adjust after a few weeks. For a custom timeframe and a target weight, use the weight loss calculator on this site.
Limits and safety
The equation is based on population averages and can be off by 10% or more for individuals. It does not take into account body composition, so a muscular person may burn more than predicted. It is also not designed for children, pregnant or breastfeeding women, or people with medical conditions.
Do not eat much less than the weight-loss figure suggests without medical advice, and avoid very low intakes. If the calculator warns that the figure is under 1,200 calories, consult a doctor or dietitian first. This tool gives general information and is not medical advice.
Frequently asked questions
How accurate is the estimate?
It is a population average and can be off by 10% or more for an individual. Track your weight for a few weeks and adjust.
Should I eat fewer than 1,200 calories?
Very low intakes should only be followed with medical supervision. The calculator warns you when the figure is low.
What is BMR?
Basal metabolic rate: the calories your body uses at rest to keep you alive. Daily needs add the energy of movement and exercise.
Which activity level should I choose?
Choose the one that matches your usual week. If unsure, choose the lower level.
Why does the result differ from other calculators?
Different equations and activity factors give different numbers. This one uses Mifflin-St Jeor, which is widely used.
Does this include exercise calories separately?
No. The activity level already includes typical exercise. Do not add exercise calories on top of it.
This calculator gives estimates for information only. Actual figures from a bank, employer, tax authority or doctor may differ. It is not financial, tax, legal or medical advice.