Calorie Calculator
By Sofia Andersen · Last updated 15 October 2026
Eat near your maintenance number and your weight tends to stay put. Eat a few hundred less each day and it tends to drift down. A few hundred more, and it tends to drift up. This calculator works out all three numbers for you, so you can see the shape of it before changing anything.
Enter your numbers
Result
General information only, not medical advice. If you have a medical condition, a history of disordered eating, or you are pregnant or breastfeeding, talk with a qualified health professional before changing how much you eat. Urgent symptoms need urgent care, not a calculator.
Start with your real week
Enter your sex, age, height, and weight, then pick the activity level that looks most like your real week, not your best week. Pick a goal, lose, maintain, or gain, and the calculator shows one target number for that goal: maintenance for maintain, maintenance minus 500 for lose, maintenance plus 300 for gain. Activity presets run from sedentary to extra active, and you can switch between them to see how much daily movement changes the total.
The setting people get wrong is activity. If you mostly sit at a desk but train hard three evenings a week, the light or moderate setting usually fits better than the athlete setting. Be honest about the other four days and the number gets a lot more useful.
Two steps, no mystery
The first step estimates your basal metabolic rate, the energy your body uses at complete rest, using the Mifflin-St Jeor equation:
Men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
Women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161
The second step turns that resting number into a daily total, called TDEE, by multiplying it by an activity factor:
| Activity level | Factor | What it looks like |
|---|---|---|
| Sedentary | 1.2 | Desk job, little exercise |
| Lightly active | 1.375 | Light exercise one to three days a week |
| Moderately active | 1.55 | Moderate exercise three to five days a week |
| Very active | 1.725 | Hard exercise six or seven days a week |
| Extra active | 1.9 | Physical job plus daily hard training |
That daily total is your maintenance level: the intake at which your weight is likely to hold steady, assuming the activity estimate is close.
A full run-through
Take a 30-year-old woman who weighs 65 kg, stands 165 cm tall, and exercises moderately.
BMR first: 10 × 65 = 650. Then 6.25 × 165 = 1,031.25. Then 5 × 30 = 150. So 650 + 1,031.25 − 150 − 161 = 1,370.25, which rounds to 1,370 calories.
Maintenance next: 1,370.25 × 1.55 = 2,123.9, which rounds to 2,124 calories a day.
A gentle deficit of 500 a day gives 2,124 − 500 = 1,624 calories. A modest surplus of 300 gives 2,124 + 300 = 2,424 calories.
All results round to the nearest whole calorie. In real life, a 500-calorie deficit rarely produces exactly a pound a week for long, because appetite, activity, and metabolism all shift as weight changes. The numbers are a starting point, and the scale over a few weeks tells you more than any single day.
Why the number moves
Think in bands, not exact targets. If maintenance comes out near 2,100, eating 2,000 to 2,200 most days will look much the same over time. Small deficits of 250 to 500 a day are the usual starting point for gradual loss, because they leave room for real food and a normal life. Very large deficits sound fast but tend to backfire: hunger, fatigue, and muscle loss, and they are hard to keep up.
Two things these estimates cannot see: what you eat, and how your body responds. Two people with the same maintenance number can feel very different on the same deficit. Sleep, stress, medication, and medical conditions all move the picture. If you have been eating far below your BMR for a while, or your weight is changing fast without trying, that is worth raising with a clinician rather than fixing with a calculator.
Frequently asked questions
How many calories should I eat to lose weight?
Many people start with a deficit of 250 to 500 calories below maintenance. That usually means slow, steady loss. A bigger deficit is not automatically better, and it is worth checking with a health professional if you have a medical condition or a lot to lose.
What is TDEE?
TDEE stands for total daily energy expenditure: everything your body burns in a day, including rest, movement, digestion, and exercise. It is your BMR times an activity factor, and it is the best estimate of your maintenance calories.
How do I calculate a calorie deficit?
Work out your maintenance calories first, then subtract. If maintenance is 2,124 and you subtract 500, you get 1,624. Track your weight for two to three weeks and adjust from there, because estimates are a starting point, not a promise.
Is a 500-calorie deficit safe?
For many healthy adults, a 500-calorie deficit is a common, gentle starting point. It is not right for everyone. If you are pregnant, breastfeeding, under 18, managing a medical condition, or have a history of disordered eating, get personal guidance first.
Why does my weight stop dropping on the same deficit?
Because the body adapts. As you get lighter, your BMR and your daily burn both fall a little, so the same intake is no longer the same deficit. Appetite often rises too. That is normal, and it is why the scale over a few weeks tells you more than any single day.
Related calculators
- BMR calculator: the resting number behind every calorie estimate.
- BMI calculator: a quick screening number from height and weight.
- Body fat percentage calculator: estimates body fat from tape measurements.
- Ideal weight calculator: a healthy weight range by height.
- How many calories should I eat?: a guide to daily intake, deficits, and maintenance.
- TDEE vs BMR: what each number means and how they fit together.
- All health calculators and all calculators on CalcKits.
This page is general information, not medical advice, a diagnosis, or treatment. It cannot replace a qualified health professional who knows your history. If symptoms worry you, or anything feels urgent, get urgent care instead of waiting on a calculator result.
Where this comes from
- Mifflin-St Jeor equation: American Journal of Clinical Nutrition (1990)
- US National Institutes of Health: Body Weight Planner concepts
- USDA: Dietary Guidelines for Americans