How many calories do you need a day?
This calorie calculator estimates how many calories you burn in a typical day — your total daily energy expenditure, or TDEE — and turns it into practical daily targets to maintain your weight, lose it gradually or put on weight. It uses the Mifflin-St Jeor equation for resting metabolism, multiplied by a standard activity factor.
Every goal is listed with its daily calories and the weekly change to expect, in kilograms or pounds. Targets never drop below the commonly used safety floors of 1,200 kcal for women and 1,500 kcal for men, and a quick protein, carb and fat split shows what the number means on your plate. Use it as a calorie deficit calculator or weight gain calculator: enter your own deficit or surplus and a goal weight to see the weeks needed.
These figures are estimates for healthy adults and are not medical advice. If you have diabetes, kidney disease, an eating disorder history or are pregnant, plan your intake with a doctor or registered dietitian.
How to use the Calorie Calculator
- Choose metric or imperial units and select your sex.
- Enter your age, height and current weight.
- Pick the activity level that matches an ordinary week — be honest; most office workers are sedentary or lightly active.
- Choose a goal: maintain, a preset loss or gain rate, or a custom calorie deficit or surplus in kcal a day. Add a goal weight to see the timeline.
- Read your daily target, the expected weekly change and the macro split. Compare every goal in the table.
Calorie Calculator features
Trusted formula
Resting metabolism comes from the Mifflin-St Jeor equation, the most accurate of the standard equations for healthy adults.
Six goals side by side
From maintenance to losing 1 kg (2 lb) or gaining 0.5 kg (1 lb) a week, with calories and weekly change for each.
Built-in safety floor
Loss targets are capped at 1,200 kcal (women) or 1,500 kcal (men), and the tool tells you when a goal is not advisable at all.
Custom deficit or surplus
Type the daily deficit or surplus you want; the weekly change and the weeks to an optional goal weight follow from it.
Quick macros
Your target is split into grams of protein, carbohydrate and fat using a balanced 30/40/30 ratio.
Metric or imperial
Use cm and kg or ft, in and lb; goals switch to pounds per week in imperial mode.
How the calculation works
Step 1 – BMR. Mifflin-St Jeor: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5 for men, or − 161 for women. See the BMR calculator to compare it with Harris-Benedict and Katch-McArdle.
Step 2 – TDEE. BMR × activity factor: 1.2 sedentary, 1.375 lightly active, 1.55 moderately active, 1.725 very active, 1.9 extra active.
Step 3 – Goal. One kilogram of body fat stores roughly 7,700 kcal (about 3,500 kcal per pound), so losing 0.5 kg a week needs a deficit of about 7,700 × 0.5 ÷ 7 = 550 kcal a day. In imperial mode, 1 lb a week means about 500 kcal a day.
Example: a 30-year-old man, 180 cm and 80 kg, has a BMR of 1,780 kcal. Moderately active, his TDEE is 1,780 × 1.55 = 2,759 kcal. To lose 0.5 kg a week he would aim for about 2,209 kcal a day. With a custom 600 kcal deficit (2,159 kcal) he loses about 0.55 kg a week, so a goal of 72 kg takes 8 × 7,700 ÷ 4,200 ≈ 14.7 weeks.
Safe rates of weight loss and gain
Health services such as the UK NHS and the US CDC suggest losing about 0.5 to 1 kg (1 to 2 lb) a week. Faster loss usually means more muscle is lost along with fat, and it is harder to keep up. Very-low-calorie diets of 800 kcal or less should only be followed under medical supervision. The NHS 12-week weight loss plan works with about 1,900 kcal a day for most men and 1,400 kcal for most women, based on earlier NICE advice to eat about 600 kcal less than you need (checked 24 October 2026).
The 7,700 kcal rule works for the first weeks but overstates long-term loss: as you get lighter, your BMR and the cost of moving fall, so progress slows. Recalculate after every 4–5 kg (about 10 lb) lost. For gaining, a surplus of 250–500 kcal with strength training favours muscle over fat.
Getting the most from your number
- Weigh yourself at the same time of day and watch the 2–3 week trend — daily weight swings by 1–2 kg.
- Keep protein high when cutting calories; the protein calculator suggests a target for your goal.
- Exercise adds to your budget — the calories burned calculator shows how much a walk, run or game of badminton is worth.
Calorie Calculator FAQ
How many calories should I eat to lose weight?
Start from your maintenance calories (TDEE) and subtract about 500–550 kcal a day to lose roughly 0.5 kg or 1 lb a week. The calorie calculator above does this for you and never goes below 1,200 kcal for women or 1,500 kcal for men.
What is TDEE?
Total daily energy expenditure is all the calories you burn in a day: basal metabolism, digesting food and all activity. Eating at your TDEE keeps your weight stable.
Why is 1,200 calories the minimum?
Below about 1,200 kcal (women) or 1,500 kcal (men) it is very hard to get enough protein, vitamins and minerals. Lower intakes are used clinically only with medical supervision.
Which activity level should I choose?
Sedentary if you sit most of the day, lightly active for 1–3 workouts a week, moderately active for 3–5. Most people overestimate activity, so if unsure, pick the lower level.
Why am I not losing weight on my calorie target?
Usually underestimated portions, oils and drinks, overestimated activity, or water retention hiding fat loss. Track carefully for two to three weeks, then lower your intake by 100–200 kcal if the trend is flat.
How do I use this as a weight gain calculator?
Choose “Custom calorie surplus”, enter 250–500 kcal and your goal weight. A surplus of 300 kcal adds roughly 0.27 kg (0.6 lb) a week; pair it with strength training and enough protein so more of the gain is muscle.
Is this calorie calculator accurate?
It uses validated equations, but any formula can be off by around 10% for an individual. Treat the result as a starting point and adjust it based on how your weight actually changes.