Calorie Calculator
Enter your age, sex, height, weight and activity level. Your daily calorie needs appear instantly.
- Maintenance calories
- —
- BMR (Mifflin-St Jeor)
- —
- Eat per day: −500 kcal (~1 lb/week)
- —
- Eat per day: −1,000 kcal (~2 lb/week)
- —
| Formula | BMR | Per day |
|---|
Everything is calculated in this page. Results are estimates, not medical advice. If you are pregnant or breastfeeding, under 19, or have a health condition, talk to a doctor or registered dietitian.
How to use
- 1. Choose unitsUS units (feet, inches, pounds) or metric (cm, kg).
- 2. Enter your detailsSex, age (19 or older), height and weight.
- 3. Pick your activity levelFour levels from the official U.S. equations, each with an example.
The NASEM 2023 equations
In 2023 the National Academies published new equations for estimated energy requirements, built from doubly labeled water measurements. For adults 19 and older there is one equation for each sex and activity level (age in years, height in cm, weight in kg).
For example, for an inactive man: 753.07 − 10.83 × age + 6.50 × height + 14.10 × weight. The typical error is about ±339 kcal a day for men and ±246 for women, so treat the result as a starting point.
| Activity level | Example (on top of daily living) | Typical PAL |
|---|---|---|
| Inactive | Daily living only | about 1.4 |
| Low active | 60–80 minutes of walking at 3–4 mph | about 1.6 |
| Active | e.g. 30–50 min walking + 45 min moderate cycling + 40 min doubles tennis | about 1.75 |
| Very active | e.g. 45 min moderate cycling + 25 min jogging + 60 min doubles tennis | about 2.05 |
Sources: NASEM (2023) Dietary Reference Intakes for Energy – Summary, Table S-3, NASEM (2023) – Chapter 7, Table 7-1
Comparing formulas
The comparison table multiplies two BMR formulas by the typical PAL of the level you chose. Mifflin-St Jeor (1990) uses weight, height, age and sex. The FAO/WHO/UNU equation (2004, based on Schofield) uses only weight, age and sex. Different formulas can differ by 100 calories or more for the same person.
Sources: Mifflin et al. (1990) American Journal of Clinical Nutrition, FAO/WHO/UNU (2004) Human energy requirements, Table 5.2
Losing weight safely
The NIH (NHLBI) practical guide says a deficit of 500 to 1,000 calories a day leads to about 1 to 2 pounds of weight loss a week. Weight loss tends to slow down over time, so adjust your target as your weight changes. The NIH Body Weight Planner does not accept goals below 1,000 calories a day.
Sources: NIH (NHLBI) The Practical Guide, NIH Body Weight Planner
FAQ
Who is this calorie calculator for?
It suits adults who want a rough idea of how much to eat each day, people who want to check their needs before trying to lose weight, people looking at needs for an adult family member or an older parent, and nutrition students who want to compare formulas side by side.
When is it useful?
For example, before you set a goal in a food-tracking app. When another site gives you a different number and you want to know why. Or to see how much your needs change if you switch from Inactive to Low active. Results update as you type.
What are the benefits of using it?
You see the official U.S. 2023 equations (NASEM) next to two other common formulas on one screen, with the sources listed on the page. You can copy the results or save them as a share link.
Which formula does this use?
The main result uses the 2023 Estimated Energy Requirement (EER) equations from the U.S. National Academies of Sciences, Engineering, and Medicine (NASEM), the basis of the U.S. Dietary Reference Intakes. BMR is shown with the Mifflin-St Jeor equation. Results are rounded to the nearest 10 kcal.
Why is my number different on other sites?
Most calorie calculators use Mifflin-St Jeor multiplied by an activity factor such as 1.2 to 1.9. Those activity factors are widely used, but we did not find them defined by a public health agency. This page shows NASEM 2023 first and lists Mifflin-St Jeor and the FAO/WHO/UNU equation underneath so you can compare.
How many calories should I cut to lose weight?
The NIH (NHLBI) guide says cutting 500 to 1,000 calories a day leads to losing about 1 to 2 pounds a week. Weight loss usually slows over time as your body uses less energy.
Which activity level should I choose?
Inactive means daily living only. Low active adds 60–80 minutes of walking at 3–4 mph per day. Active adds, per day, something like 30–50 minutes of walking, 45 minutes of moderate cycling and 40 minutes of doubles tennis. Very active adds, per day, something like 45 minutes of moderate cycling, 25 minutes of jogging and 60 minutes of doubles tennis. The description appears under the menu when you choose.
How accurate is the result?
It is an estimate. NASEM reports a typical error of about ±339 kcal a day for men and ±246 for women, so treat the result as a starting point and adjust it as your weight changes.
Does my height change the result?
Yes. The NASEM equations use your age, height and weight for your sex and activity level, so changing any of them changes the result. In the comparison table, Mifflin-St Jeor also uses height, while the FAO/WHO/UNU equation uses only weight, age and sex.
What does the BMR number mean here?
The BMR shown is calculated with the Mifflin-St Jeor equation. The main daily number comes from the NASEM equation for your activity level, not from BMR times a factor. The comparison table lists BMR from two formulas, each multiplied by the typical PAL for your level.
Why does it say “Under 1,000 kcal” or show a dash?
If cutting calories would take you below 1,000 kcal a day, that number is hidden and shows “Under 1,000 kcal”, because the NIH Body Weight Planner does not allow goals that low. If your BMI is under 18.5 (underweight), weight-loss targets are not shown at all.
How low can the calorie target go?
The NIH Body Weight Planner does not allow goals below 1,000 calories a day. Very-low-calorie diets (under 800 calories a day) are not for routine use, according to the NHLBI practical guide, and the NHS says they should only be followed with support from a healthcare professional. Talk to a doctor or dietitian before cutting a lot.
Does it show calories for gaining weight?
No. We did not find an official public health guideline for how much to add, so gain targets are not shown. Use your maintenance calories as a reference and adjust as your weight changes.
Can I use it for children or during pregnancy?
No. The equations here are for adults 19 and older; children and teens need different equations that include growth. Pregnancy and breastfeeding are not covered by this calculation. Talk to a doctor or registered dietitian.
Can older adults use it?
Yes. The NASEM adult equations cover ages 19 and older and use your exact age. In the comparison table, the FAO/WHO/UNU equation uses its own age group for 60 and older.
Is my data sent anywhere?
No. The calculation happens in your browser. The share link stores your numbers after the # in the URL, which is not sent to the server.
What is the difference between “Share link” and “Copy results”?
Share link copies a link with your units, sex, age, height, weight and activity level after the #. Opening it runs the same calculation. Copy results copies the result lines together with that link. Anyone with the link can see those numbers, so share it with care.
What range of numbers can I enter?
The calculator works for ages 19 and older, heights from 100 to 250 cm (about 3 ft 3 in to 8 ft 2 in) and weights from 25 to 300 kg (about 55 to 661 lb). Outside that range it shows a message asking you to check your entries.
Does it work on a phone?
Yes. On a narrow screen the results appear below the input boxes, and the formula comparison table scrolls sideways.
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