Calorie CalculatorFree online fitness & health calculator — instant results, no sign-up
Daily calories to maintain, lose or gain weight.
For general information only. This is not medical advice, diagnosis, dosing guidance or a treatment recommendation. Talk to a doctor or other qualified health professional about your health, pregnancy, or diet.
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How the result changes with age
Each row below was calculated with this tool, keeping every other input at its default and changing only age from half to one and a half times the default value. Use it to see how sensitive the answer is before you enter your own numbers.
| Age (years) | Maintain | Mild loss (0.25 kg/wk) | Loss (0.5 kg/wk) |
|---|---|---|---|
| 15 | 2,749 kcal/day | 2,499 kcal/day | 2,249 kcal/day |
| 23 | 2,687 kcal/day | 2,437 kcal/day | 2,187 kcal/day |
| 30 (default) | 2,633 kcal/day | 2,383 kcal/day | 2,133 kcal/day |
| 38 | 2,571 kcal/day | 2,321 kcal/day | 2,071 kcal/day |
| 45 | 2,517 kcal/day | 2,267 kcal/day | 2,017 kcal/day |
About the Calorie Calculator
This calculator estimates your daily energy expenditure to determine calorie targets for maintaining, losing, or gaining body weight. It uses your personal metrics and activity level to estimate baseline metabolic needs and applies standard caloric adjustments for weight management goals.
- Age
- Age in completed years; sensible range is typically 15 to 100.
- Sex
- Biological sex (Male or Female), used to calculate basal metabolic rate.
- Height
- Stature in centimeters; typical adult range is 120 to 220 cm.
- Weight
- Current body mass in kilograms; typical adult range is 30 to 250 kg.
- Activity
- Weekly physical activity level, categorized from Sedentary to Very active.
Formula and method
BMR (Male) = 10 × w + 6.25 × h − 5 × age + 5 BMR (Female) = 10 × w + 6.25 × h − 5 × age − 161 TDEE = BMR × Activity Multiplier Maintain = TDEE Mild loss = TDEE − 250 Loss = TDEE − 500 Extreme loss = TDEE − 1000 Gain = TDEE + 500
- BMRBasal Metabolic Rate in kcal/day
- wBody weight in kilograms (kg)
- hHeight in centimeters (cm)
- ageAge in years
- TDEETotal Daily Energy Expenditure in kcal/day
- Activity MultiplierFactor based on weekly exercise: Sedentary (1.2), Light (1.375), Moderate (1.55), Active (1.725), or Very active (1.9)
The tool first calculates your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor formula, then scales it by an activity coefficient to calculate Total Daily Energy Expenditure (TDEE). Calorie targets for weight adjustment are then derived by subtracting or adding fixed daily caloric increments (250, 500, or 1,000 kcal/day), rounded to the nearest whole calorie.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Age30 years
- SexMale
- Height175 cm
- Weight75 kg
- ActivityModerate (3-5 days/wk)
Results
- Maintain2,633 kcal/day
- Mild loss (0.25 kg/wk)2,383 kcal/day
- Loss (0.5 kg/wk)2,133 kcal/day
- Extreme loss (1 kg/wk)1,633 kcal/day
- Gain (0.5 kg/wk)3,133 kcal/day
How to use the Calorie Calculator
- 1Calculate baseline BMR from age, sex, height (cm), and weight (kg) using the Mifflin-St Jeor equation.
- 2Multiply BMR by the selected physical activity multiplier (1.2 to 1.9) to find maintenance calories (TDEE).
- 3Subtract 250, 500, or 1,000 kcal/day from maintenance to find daily targets for 0.25 kg, 0.5 kg, and 1 kg weekly loss.
- 4Add 500 kcal/day to maintenance to calculate the target for gaining 0.5 kg per week.
Reading your result
The 'Maintain' value represents the estimated daily calories needed to keep your current weight stable at your current activity level. Deficit figures indicate daily caloric intake targets for reducing weight at specific rates, while the surplus figure provides an intake target for gradual weight gain.
Limitations
The Mifflin-St Jeor formula assumes average body composition and does not directly measure muscle mass versus fat mass. The calculation also assumes a constant energy deficit translates linearly into weight change, which does not account for metabolic adaptation over time.
Common questions
Why are 500 calories subtracted for a 0.5 kg weekly loss?+
One kilogram of body fat corresponds approximately to 7,700 kcal, so losing 0.5 kg requires a cumulative weekly deficit of about 3,500 kcal, or 500 kcal per day.
Is the extreme loss deficit of 1,000 kcal safe for everyone?+
A 1,000 kcal deficit represents a steep reduction that may cause nutrient inadequacies or excessive muscle loss, especially for individuals with lower starting maintenance requirements.
Does this calculator account for exercise calories separately?+
No, exercise is accounted for as an aggregate category through the selected activity multiplier rather than logged as individual workouts.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
Further reading
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Results are estimates for informational purposes and are not financial, medical or legal advice.