Estimate daily calorie needs without treating the result as exact

This calculator estimates basal metabolic rate (BMR) and total daily energy expenditure (TDEE). It then shows a clearly labelled working range for maintenance, gradual weight loss or gradual weight gain.

The result is a general estimate, not an optimal intake, prescription or guaranteed rate of weight change. Real energy needs can differ because of body composition, daily movement, training, health, pregnancy, growth and other factors the calculator does not measure.

How to use the calorie calculator

1. Choose Metric or Imperial units.
2. Enter your age, the sex category required by the equation, height and weight.
3. Select the activity category that most closely describes your usual week.
4. Choose Maintain weight, Gradual weight loss or Gradual weight gain.

The calculator accepts adults aged 18–120. Valid height is 100–250 cm, or 39.4–98.4 in. Valid weight is 30–300 kg, or 66.1–661.4 lb. If an entry falls outside these bounds, the result is replaced by a clear input-check message.

What the results mean

Estimated BMR is the predicted energy your body uses at rest. It is not a recommended minimum food intake.

Estimated maintenance (TDEE) multiplies BMR by the selected activity factor. This is the calculator’s central estimate for average daily energy expenditure at the entered activity level.

Goal range keeps maintenance separate from the selected scenario:

• Maintain weight: about 5% either side of estimated TDEE.
• Gradual weight loss: about 10–15% below estimated TDEE.
• Gradual weight gain: about 5–10% above estimated TDEE.

These percentages are cautious comparison scenarios. They do not promise a particular weekly change, and the calculator does not create a meal plan or set macronutrient targets.

Mifflin–St Jeor calculation

The calculator uses the Mifflin–St Jeor equation, developed as a predictive equation for resting energy expenditure. Weight is measured in kilograms (W), height in centimetres (H), and age in years (A):

• Male equation: BMR = 10W + 6.25H − 5A + 5
• Female equation: BMR = 10W + 6.25H − 5A − 161

The equation categories reflect the variables used by the published formula; they do not capture every individual difference in body composition or metabolism. The original Mifflin–St Jeor paper describes the underlying predictive equation.

Imperial entries are converted before calculation:

• kilograms = pounds × 0.45359237
• centimetres = inches × 2.54

The calculator rounds displayed BMR, TDEE and goal ranges to whole kilocalories per day. Small differences of about one calorie can appear between equivalent metric and imperial entries because the visible fields accept measurements to one decimal place.

Activity factors used for TDEE

TDEE is estimated as BMR × activity factor. The calculator uses these five broad categories:

These factors are also documented in the American Council on Exercise overview of resting metabolic rate and TDEE. Activity labels are necessarily broad: a job, step count, training volume and recovery can affect daily expenditure in ways a single dropdown cannot capture.

Verified example

For a 30-year-old male, 175 cm tall and 70 kg, with Sedentary selected, the calculator returns:

• estimated BMR: 1,649 kcal/day;
• estimated maintenance: 1,979 kcal/day; and
• maintenance working range: 1,880–2,078 kcal/day.

Changing only the activity category changes TDEE while leaving BMR unchanged. For the same example, the tested TDEE values range from 1,979 kcal/day at Sedentary to 3,133 kcal/day at Extra active.

Limits and health disclaimer

This tool is for general adult education and planning. It is not a diagnosis, medical treatment or individual nutrition advice. It is not designed for people under 18, pregnancy or breastfeeding, elite-sport planning, illness, or eating-disorder care. The NIDDK Body Weight Planner uses similar adult-only limitations and advises consulting a healthcare provider for specific health questions.

A predicted BMR can differ from measured resting energy expenditure, and the activity factor can be the largest source of uncertainty. If the estimate is unusually low or high, if your weight changes differently from the scenario, or if health or eating concerns are involved, speak with a qualified healthcare or nutrition professional.

Frequently asked questions

Why is my result different from a wearable or another calculator?

Wearables may use movement, heart rate and proprietary models. Other calculators may use a different resting-energy equation or activity assumptions. Differences are expected and do not prove that one estimate is exact.

Does BMR mean the minimum I should eat?

No. BMR is a predicted resting-energy value used inside the calculation. It is not a personalised intake recommendation.

Which activity level should I choose?

Choose the category that best reflects your usual overall pattern, including daily movement and physical work as well as exercise. If you are between categories, compare both results and treat the spread as part of the uncertainty.

Does the calculator include exercise calories separately?

No. The activity factor is already part of TDEE, and this tool does not add individual workouts. To estimate the energy used during a specific activity, use the separate MET Calculator.