Free Calorie Calculator – Calculate Daily Calorie Needs

How the Calorie Calculator Works and What TDEE Means

A calorie calculator estimates how much energy your body actually uses in a day, a figure nutritionists call Total Daily Energy Expenditure or TDEE. It starts from the calories you burn simply existing — breathing, pumping blood, keeping warm — and then adds the cost of moving around, working, and training. You supply five things: age, gender, height, weight, and how active a typical week looks. In return you get three numbers: the calories that hold your weight steady, a lower target for losing weight, and a higher one for gaining. People reach for this when a diet has stalled, when they are starting a gym plan and have no idea what to eat, or when they want to stop guessing portion sizes and work from a real figure instead. Underneath sit two steps. First, Basal Metabolic Rate comes from the Mifflin-St Jeor equation, which studies have found closer to measured metabolism than the older Harris-Benedict formula for most adults. For men, BMR = 10 × weight in kg + 6.25 × height in cm − 5 × age + 5; for women the final term is −161 instead of +5. Second, that BMR is multiplied by an activity factor: 1.2 for a desk-bound life, 1.375 for light exercise one to three days a week, 1.55 for three to five days, 1.725 for hard daily training, and 1.9 for physical labour plus training. The product is your maintenance level. Subtracting roughly 500 calories a day sets up steady fat loss; adding 500 supports a lean gain. Run a real profile through it. A 30-year-old man weighing 75 kg at 175 cm who trains four days a week: 10 × 75 = 750, plus 6.25 × 175 = 1,093.75, minus 5 × 30 = 150, plus 5, giving a BMR of 1,698.75 calories. Multiply by the moderate factor of 1.55 and his TDEE lands at about 2,633 calories a day. That is his maintenance figure. For fat loss he would aim near 2,133, and for a gaining phase around 3,133. Notice how much of the total comes from activity — nearly 950 calories in this case, which is why picking the right factor matters more than fussing over the decimal places in BMR. The practical uses are specific. Someone who has been eating 1,400 calories and stopped losing weight discovers their maintenance is 2,600 and realises the problem is a deficit so aggressive that metabolism and adherence both suffered. A skinny 21-year-old trying to add muscle finds he needs 3,100 calories, not the 2,200 he had been eating, and understands why the scale has not moved in six months. A woman preparing for a half marathon sees her needs rise from 1,900 to 2,300 on heavy training weeks and plans her carbohydrates accordingly. A parent packing lunches for a teenage athlete uses the figure to size portions rather than eyeballing them. In each case the number turns a vague intention into a plan you can measure against. A few honest limits. This is a population-average estimate, not a metabolic test; genetics, muscle mass, thyroid function, medication, and sleep all shift real needs by a few hundred calories either way. The mistake almost everyone makes is over-rating their activity level — a gym session three times a week alongside a desk job is light-to-moderate, not very active, and choosing the wrong factor can inflate your target by 400 calories and quietly stall progress. Weigh yourself over two weeks and adjust the number based on what actually happens rather than trusting the first estimate. Very low targets are unsafe, and this is not built for children, pregnant or breastfeeding women, or anyone with a medical condition; talk to a doctor or registered dietitian before making big dietary changes. Nothing here is medical advice, and the whole calculation runs in your browser, so your body measurements are never uploaded or stored.

Calorie Calculator Formula & Method

Learn More — Calorie Calculator Guide

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