Free tool · Health
Calorie Calculator
See the calories your body burns at rest, the level that maintains your weight, and planning targets for your goal.
Daily calories for a 30-year-old woman, 65 kg and 165 cm?
Estimated calories to maintain your current weight.
The deficit target falls below 1,200 kcal a day. Intakes that low need a clinician's supervision — treat the maintenance figure as your anchor instead.
How to use this calorie calculator
- Choose Metric (kilograms and centimetres) or Imperial (pounds, feet and inches).
- Enter your age, sex, weight and height, then pick the activity level that honestly matches a normal week.
- Read the large figure: your estimated maintenance calories for the day. The rows underneath give your BMR and common planning targets.
- Use the targets as planning figures for a week or two, watch the trend, and adjust. They are estimates, not a prescription.
The formula
This calculator uses the Mifflin-St Jeor equation, the formula most often recommended for estimating resting energy needs in adults. It first works out your BMR — the calories your body burns at complete rest — then multiplies it by an activity factor to estimate your daily maintenance level.
BMR — metric
10 × kg + 6.25 × cm − 5 × age + 5 (men) or − 161 (women)
Weight in kilograms and height in centimetres go in; resting calories come out.
BMR — imperial
4.536 × lb + 15.875 × in − 5 × age + 5 (men) or − 161 (women)
The same equation expressed in pounds and total inches, so no conversion step is needed.
Maintenance
Maintenance = BMR × activity factor (1.2 to 1.9)
The factor stands in for everything you do beyond resting: work, walking, training and daily movement.
Worked example: a 30-year-old woman of 65 kg and 165 cm has a BMR of 10 × 65 + 6.25 × 165 − 5 × 30 − 161 = 1,370 kcal. At a moderate activity factor of 1.55, her maintenance level is 1,370 × 1.55 = 2,124 kcal a day. The deficit and surplus rows simply move 250 or 500 kcal below or above that anchor — planning figures people commonly start from, not promised rates of change.
One caution is built in: if a deficit target falls below 1,200 kcal a day, the calculator flags it. Intakes that low should only be followed with a clinician's supervision.
Examples
| Person | BMR | Maintenance |
|---|---|---|
| Woman, 30, 65 kg, 165 cm, moderately active | 1,370 kcal | 2,124 kcal |
| Man, 40, 85 kg, 180 cm, moderately active | 1,780 kcal | 2,759 kcal |
| Woman, 55, 60 kg, 160 cm, sedentary | 1,164 kcal | 1,397 kcal |
Frequently asked questions
How many calories should I eat a day?
Start from your maintenance level — the figure this calculator shows in large type. Eating near it tends to hold your weight steady. Eating below it or above it moves the trend down or up over time. Your own trend over two to three weeks is a better guide than any single estimate.
How accurate is this calculator?
The Mifflin-St Jeor equation is one of the most accurate formulas for adults, but it is still an estimate: real energy needs vary with body composition, health, medication and how active a day actually is. Treat the result as a starting point and adjust from what your weight and energy actually do.
What is the difference between BMR and maintenance (TDEE)?
BMR is what your body burns at complete rest — keeping you warm, breathing and circulating blood. Maintenance, often called TDEE, is BMR plus everything else you do in a day. You plan your eating around maintenance, not BMR.
How large a deficit is sensible?
Planning figures of 250 to 500 kcal below maintenance are the common starting range shown on this page. Larger deficits and any target under 1,200 kcal a day belong under a clinician's supervision. This page gives calculation aids, not prescriptions, and it does not promise any rate of weight change.
Can teenagers use this calculator?
The Mifflin-St Jeor equation was developed for adults, so this calculator is built for ages 15 and up and its results are adult estimates. Children and younger teenagers have growth needs these equations do not cover; a pediatrician or dietitian is the right source for them.
Why does the activity level change the result so much?
Because the multiplier runs from 1.2 for a sedentary day to 1.9 for athlete-level training, and it acts on your whole BMR. Picking the level that honestly matches a normal week matters more than small differences in weight or height.
Privacy and important information
This tool runs in your browser: your age, sex, weight, height and activity entries are calculated on your device and are not sent to or stored on our servers, and no account is needed. You can use it with an ordinary internet connection today, and your entries remain under your control.
The figures are estimates from a standard equation, provided for general information and planning. They are not medical advice and do not replace guidance from a clinician or dietitian, especially if you are pregnant, managing a condition, or planning a large change in intake.