Calorie Calculator
Find how many calories you need a day to maintain, lose or gain weight. Based on the Mifflin-St Jeor equation, your activity level and safe intake limits.
🔥 Calorie Calculator
Daily Calories
💡 How Many Calories Do You Need a Day?
The calculator estimates three daily calorie targets: one to maintain your weight, one for gradual weight loss and one for weight gain. It calculates your maintenance calories from your age, sex, height, weight and activity level, then subtracts or adds 500 kcal for the loss and gain targets. For a 30-year-old man of 70 kg and 170 cm with moderate activity, that is 2,507 kcal to maintain, 2,007 kcal to lose and 3,007 kcal to gain.
How the targets are calculated
2. Maintenance = BMR × activity factor (1.2 sedentary, 1.375 light, 1.55 moderate, 1.725 active, 1.9 very active)
3. Weight loss = maintenance − 500 kcal · Weight gain = maintenance + 500 kcal
The Mifflin-St Jeor equation was rated the most reliable of the common equations in a 2005 systematic review. For the full breakdown at every activity level, see the TDEE calculator.
Calorie targets for example people
| Person | Maintain | Lose (−500) | Gain (+500) |
|---|---|---|---|
| Man, 30, 70 kg, 170 cm, moderate | 2,507 | 2,007 | 3,007 |
| Man, 45, 90 kg, 180 cm, sedentary | 2,166 | 1,666 | 2,666 |
| Man, 25, 80 kg, 183 cm, active | 3,146 | 2,646 | 3,646 |
| Woman, 35, 60 kg, 165 cm, moderate | 2,008 | 1,508 | 2,508 |
| Woman, 50, 75 kg, 162 cm, light | 1,858 | 1,358 | 2,358 |
| Woman, 50, 50 kg, 160 cm, sedentary | 1,307 | 807 ⚠️ | 1,807 |
⚠️ The last example shows why the −500 rule can't be applied blindly: a smaller, older, sedentary woman would get a weight-loss target of only 807 kcal. Harvard Health advises that calorie intake should not fall below 1,200 a day for women or 1,500 a day for men except under the supervision of a health professional, and the calculator now shows a warning when its weight-loss figure falls below these levels. Diets of about 800 kcal or less (very low-calorie diets) are a medical treatment that needs supervision.
Official estimates of daily calorie needs
The Dietary Guidelines for Americans 2020–2025 publish these estimated needs for adults. "Not active" means only the light activity of daily life; "moderately active" adds walking about 1.5–3 miles a day at 3–4 mph; "active" adds walking more than 3 miles a day at that pace.
| Age | Women: not active | Women: moderately active | Women: active | Men: not active | Men: moderately active | Men: active |
|---|---|---|---|---|---|---|
| 19–30 | 1,800–2,000 | 2,000–2,200 | 2,400 | 2,400–2,600 | 2,600–2,800 | 3,000 |
| 31–50 | 1,800 | 2,000 | 2,200 | 2,200–2,400 | 2,400–2,600 | 2,800–3,000 |
| 51+ | 1,600 | 1,800 | 2,000–2,200 | 2,000–2,200 | 2,200–2,400 | 2,400–2,800 |
These are population averages for people of typical height and weight. The calculator personalises the estimate using your own measurements. The newer 2025–2030 edition of the guidelines, released in January 2026, keeps the principle of eating the right amount for your own needs.
What a 500-calorie change means
- Weight loss: Harvard Health notes that eating at least 500 calories less than your maintenance intake each day leads to losing roughly a pound (about 0.45 kg) a week at first. Weight loss usually slows over time because a smaller body needs less energy, so targets need updating as your weight changes.
- Weight gain: a surplus adds weight, but how much is muscle depends heavily on protein intake and strength training. Many people aiming for lean gain use a smaller surplus.
- Maintenance: day-to-day intake can vary; what matters is the average over a week or more.
Where calories come from
Food energy comes from four sources, each with a standard energy value per gram:
| Nutrient | Calories per gram | Example |
|---|---|---|
| Protein | 4 kcal | 30 g protein = 120 kcal |
| Carbohydrate | 4 kcal | 50 g carbs = 200 kcal |
| Fat | 9 kcal | 15 g fat = 135 kcal |
| Alcohol | 7 kcal | 14 g alcohol (one US standard drink) = 98 kcal |
Because fat has more than twice the energy of protein or carbohydrate, small amounts of oils, nuts and butter add calories quickly. To plan how your calories divide between protein, carbs and fat, use the macro calculator.
Reading calories on food labels
- Calories, Calories and kcal: the "Calories" on food labels are kilocalories (kcal). A food listed as 250 Calories contains 250 kcal.
- Kilojoules: some countries list energy in kJ. 1 kcal = 4.184 kJ, so 1,000 kJ is about 239 kcal.
- Serving size: check it. A packet may contain two or more servings, and the calories listed are per serving.
Tips for more accurate results
- Choose a realistic activity level. Overestimating activity is the most common reason targets are too high.
- Treat the result as a starting point. Track your weight for 2–3 weeks: if it stays steady, your intake is your real maintenance level; adjust from there.
- Recalculate after weight change of a few kilograms, since your needs change with your weight.
- Consider body composition. Very muscular people may need more than the equation suggests; the body fat calculator and lean body mass calculator can help.
This calculator is designed for healthy adults. It isn't suitable for children, pregnant or breastfeeding women, or people with medical conditions. If you have a history of disordered eating, or are planning a large change in diet, speak to a doctor or registered dietitian first.
Sources
- Estimated calorie needs, Dietary Guidelines for Americans 2020–2025 (via UMass Memorial Health)
- Oklahoma State University Extension: The new Dietary Guidelines for Americans 2025–2030
- Harvard Health Publishing: Calorie counting made easy
- Frankenfield et al. (2005), Journal of the American Dietetic Association: comparison of resting metabolic rate equations
- NIDDK (NIH): very low-calorie diet