What this calorie calculator tells you
Everything your body does costs energy, measured in calories. Eat about what you burn and your weight stays put. Eat less and your body draws on stored fat; eat more and it stores the extra. The calculator estimates your burn from age, sex, height, weight, and activity, then shows the intake for each goal: maintain, three rates of loss, and gain. One number does not fit everyone, and that is the point — a small, lightly active woman and a tall manual worker can sit 1,500 calories apart.
How many calories do you need a day?
Most adult women maintain on roughly 1,600–2,400 calories a day, most adult men on 2,000–3,000. The reference ranges below come from the Dietary Guidelines for Americans and span sedentary to active:
| Age | Women | Men |
|---|---|---|
| 19–30 | 1,800–2,400 | 2,400–3,000 |
| 31–50 | 1,800–2,200 | 2,200–3,000 |
| 51+ | 1,600–2,200 | 2,000–2,800 |
Treat these as population averages, useful for context and nothing else. Your height, weight, and actual week of movement matter more than your age bracket, which is why the calculator asks for all of them.
Calories to lose weight
Weight loss means eating below the maintain number. A cut of 250–500 calories a day produces about 0.25–0.5 kg (0.5–1 lb) per week, a pace most people can hold without misery. The 1 kg-per-week row requires a much larger cut; it fits higher starting weights and goes better with professional support. Two guardrails are built in: targets never drop below 1,200 calories, and nothing faster than 1 kg per week is offered. For deficit sizing, goal dates, and the honest math behind them, the calorie deficit calculator is the next step.
Calories to gain weight
Gaining works the same way in reverse: eat 250–500 above maintenance. Slower is leaner. A 250-calorie surplus adds roughly 0.25 kg a week, and paired with strength training more of that weight is muscle. To decide where the extra calories should come from, the macro calculator splits your target into protein, carb, and fat grams.
What a calorie change looks like in food
Numbers stick better when they are meals. A 250-calorie cut is one large latte and a biscuit, or a pint of beer, or two tablespoons of olive oil left out of the pan. A 500-calorie cut is a fast-food cheeseburger, a medium portion of fries, or swapping two sugary sodas for water. Going the other way, a 250-calorie surplus is a peanut butter sandwich, or a large banana with a glass of milk. No food here is forbidden on any plan. The point is that a daily target only moves when a few concrete choices move with it, and drinks and cooking fats are usually the cheapest places to start.
Where the numbers come from
The calculator estimates resting burn with the Mifflin-St Jeor equation, the formula clinical dietitians default to, then multiplies by an activity factor between 1.2 and 1.9. Resting burn on its own is the BMR calculator’s job, and the full method — equations, multiplier table, and a body-fat option — lives on the TDEE calculator page. Expect the result to land within about 10% of reality. The activity level you pick is the biggest source of error, so choose the lower one when torn.
Making your calorie target work
Eat to the same number every day rather than cycling it; consistency is what shows up on the scale. Weigh in the morning and judge weekly averages, since daily readings swing 1–2 kg on water alone. Count drinks, cooking oils, and sauces, because that is where most untracked calories hide. And rerun the calculator after every 4–5 kg of change: the target that loses weight at 90 kg merely maintains it at 80.
