Use the free Daily Calorie Calculator below: your data never leaves your browser — all work happens on your device, and nothing is uploaded to any server.
What This Calculator Does
A daily calorie calculator answers a simple question: how much food energy does your body need each day? Your body burns calories even at rest. It burns more when you move, work, and train. This tool adds those two parts together. First it estimates your basal metabolic rate, or BMR. That is the energy you would burn if you lay still all day. Then it multiplies that number by an activity factor. The result is your total daily energy expenditure, or TDEE. That is the number of calories that keeps your weight steady.
The tool also shows two nearby targets. One is 500 calories below maintenance, a gentle deficit for slow weight loss. The other is 500 calories above maintenance, a gentle surplus for slow weight gain. A deficit of 500 calories a day works out to roughly half a kilogram of fat loss per week for most people, because a kilogram of body fat stores about 7,700 calories. These are averages, not promises. Real bodies vary with sleep, stress, hormones, and muscle mass.
How to Use It
Choose your sex, then type your age, height in centimetres, and weight in kilograms. Next pick the activity level that best matches your real life, not the life you wish you had. A desk worker who trains three times a week is lightly or moderately active, not very active. Click Calculate. You will see your maintenance calories first, then the lose and gain targets. If your weight changes over time, come back and re-run the numbers with your new weight, because a lighter body needs fewer calories.
The Formula, Explained
This calculator uses the Mifflin-St Jeor equation, which dietitians widely use because it fits most adults well. For men it is 10 times weight in kilograms, plus 6.25 times height in centimetres, minus 5 times age in years, plus 5. For women the same formula ends with minus 161 instead of plus 5. The difference reflects average differences in muscle mass. The activity factors are standard: 1.2 for sedentary, 1.375 for lightly active, 1.55 for moderately active, 1.725 for very active, and 1.9 for extra active people with physical jobs and hard training.
A Worked Example
Take a 30-year-old man who is 170 centimetres tall, weighs 70 kilograms, and is moderately active. His BMR is 10 times 70, plus 6.25 times 170, minus 5 times 30, plus 5, which equals 1,617.5 calories. Multiply by 1.55 and you get about 2,507 calories a day to maintain weight. His gentle weight-loss target is about 2,007 calories, and his gentle weight-gain target is about 3,007 calories. If he eats at the loss target and his weight stalls for three weeks, he can check his activity level first, since people often overestimate how active they are.
Common Mistakes
The biggest mistake is picking too high an activity level, which inflates the result and stalls weight loss. The second is treating the number as exact. It is an estimate. Food labels can be off by 10 percent, and so can your tracking. Judge the number by results over two to four weeks, not by one day on the scale. Daily weight jumps up and down with water, salt, and food volume. Weigh yourself a few times a week and watch the trend.
Frequently Asked Questions
Should I eat below my BMR? In general, no. Eating far below BMR for a long time leaves you tired, hungry, and more likely to lose muscle. A small deficit below maintenance is safer and easier to keep up. Do I need to count every calorie forever? No. Many people track for a few weeks to learn portion sizes, then eat by habit. Does the calculator work for athletes? Very muscular or very active people may need more than the estimate, because the formula uses weight, not muscle mass. Use results over time to adjust.
Educational estimate only. This is not medical advice. Talk to a health professional before changing your diet or starting a weight-loss plan, especially if you have a medical condition, are pregnant, or take medication.
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