Calorie calculator: estimate your daily needs.
Your calorie needs depend on factors including age, body size and activity. This calculator uses the Mifflin–St Jeor equation to estimate resting energy expenditure, then multiplies it by your selected activity factor. It is a calculation for adults, not a measurement or a personal dietary recommendation. The equation cannot determine which intake or weight-loss goal is appropriate for you.
Free during beta. No credit card required.
Estimate your daily calorie needs
Enter your age, weight and height to calculate your estimated needs.
Mifflin–St Jeor equation (Am J Clin Nutr, 1990): an estimate for healthy adults, not medical advice.
What are maintenance calories?
Maintenance calories correspond to total daily energy expenditure, or TDEE. This calculator estimates that amount. For example, the female equation with age 34, weight 78 kg and height 172 cm gives a resting estimate of 1,524 kcal. An activity factor of 1.375 gives about 2,096 kcal per day. This example is not a personal recommendation or a promise about weight change.
How are your daily calorie needs calculated?
The calculator uses the rounded Mifflin–St Jeor equation for resting energy expenditure (REE). Male equation: 10 × weight in kg + 6.25 × height in cm − 5 × age + 5. Female equation: the same calculation with −161 instead of +5. The original study included healthy adults aged 19–78. The app then applies an activity factor between 1.2 and 1.9. This additional step estimates daily expenditure; it does not measure exact maintenance needs.
| Equation | Resting energy equation |
|---|---|
| Male | 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + 5 |
| Female | 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) − 161 |
How does activity affect the result?
Your selected factor can substantially change the estimate. Exercise frequency alone cannot measure activity throughout a whole day. The factors below are an addition to the Mifflin equation, not findings from its original study. NNR 2023 uses different reference calculations with the Henry equation and activity levels including PAL 1.4, 1.6 and 1.8; these are distinct from the app's choices.
| Level | Factor | Calculator description |
|---|---|---|
| Sedentary | 1.2 | Desk work and no regular exercise |
| Lightly active | 1.375 | Exercise or brisk walking 1–3 days a week |
| Moderately active | 1.55 | Exercise 3–5 days a week |
| Very active | 1.725 | Hard exercise 6–7 days a week |
| Extremely active | 1.9 | Physical work plus daily exercise |
How many calories should you eat to lose weight?
Weight loss involves an energy deficit over time, but its size and the diet's composition must suit the person. The calculator's goal adjustment is a selected arithmetic step, not a recommendation to eat that amount. If weight loss is appropriate for you, a doctor or registered dietitian can help with a suitable plan. NICE recommends professional support for energy-restricted programmes; very low intakes should not be chosen using an app alone.
How accurate is the result?
It is an estimate, not a measurement. People with the same inputs can have different energy expenditure, and we have not measured a general error margin for this calculator. Body composition, illness, medication and activity can affect needs. Neither an equation nor a few weeks of weight fluctuations can establish your precise requirements on its own.
Who should seek individual guidance first?
This calculator is intended for healthy adults. If you are under 18, pregnant or breastfeeding, have a current or past eating disorder, take medication affecting weight, appetite or blood glucose, or have diabetes, kidney disease or another chronic condition, speak with your doctor or a registered dietitian before using a calorie target. This page does not provide medical advice.
What are the sources?
The Mifflin study describes resting energy expenditure; NNR describes Nordic reference requirements. Neither measures this calculator's accuracy or replaces individual guidance.
Frequently asked questions
How many calories should I eat each day?
It depends on the person. This calculator gives a Mifflin–St Jeor estimate based on body size, age, equation variant and selected activity level. The result is not a measurement or a personal dietary recommendation.
What is the difference between BMR and TDEE?
BMR is basal metabolic rate under standardised conditions; resting energy expenditure (REE) is a related measure. The Mifflin equation estimates REE. TDEE includes energy used throughout the day, including activity. The app estimates TDEE by multiplying the equation's result by a selected activity factor.
How large should a calorie deficit be?
There is no single suitable deficit for everyone. The calculator can show a selected adjustment but cannot determine a safe intake or programme. A doctor or registered dietitian can help you choose a plan for your circumstances.
How much energy do I use each day?
The calculator combines a resting estimate with your selected activity factor. Your actual expenditure may differ, and broad exercise categories do not measure all daily movement. The equation's inputs are not enough to determine a precise individual value.
Is the calculator free?
Yes. Use it without an account. Basic Calorie.one tracking is free during beta, with no payment card required. With an account, you can choose a daily budget and log meals against it.
How can I use the result?
Use the app to record food and display a target you choose. A calculated number is an estimate and should not automatically become a dietary plan. Text and photo analysis use USDA matches when available and labelled estimates otherwise. Check each source and portion before saving.
Why might my weight differ from the prediction?
Energy estimates, food records and short-term weight fluctuations can all contribute. The app cannot determine the cause or diagnose a condition. Avoid lowering intake based only on a few measurements; speak with your doctor if you are concerned or unsure.