Calories

Calorie Calculator

Details

How to use Calorie Calculator

What the tool does, how to run it, and what to expect from the result.

How to calculate your daily calories

Enter weight in kilograms, height in centimeters, age, sex, and an activity level. The tool computes a Mifflin-St Jeor basal metabolic rate, multiplies it by the activity factor, and shows the result as maintenance calories, along with a mild loss and a mild gain target 275 kcal either side.

The equation is the best of the common predictive formulas, and it is still a prediction, with roughly 10 percent error before the activity multiplier adds its own. Use the number as a starting point and let three weeks of scale data tell you whether it was right.

  • Enter weight, height, and age, and select your sex.
  • Choose an activity level, taking the conservative option if you are between two.
  • Read the maintenance figure, which is what holds your current weight.
  • Use the mild loss or mild gain line (275 kcal either side, about 0.25 kg a week) rather than a large jump.
  • Eat to the target for two to three weeks, track the weekly trend, and adjust the calories from what you observe.

What the numbers work out to

The resting figure is Mifflin-St Jeor: 10 times weight in kilograms, plus 6.25 times height in centimeters, minus 5 times age in years, then plus 5 for men or minus 161 for women. Multiplying by the activity factor turns that resting figure into maintenance.

For a 30-year-old man at 70 kg and 175 cm, the resting figure is 1,649 kcal. On Moderate (1.55) that gives 2,556 kcal of maintenance, with 2,281 kcal on the mild loss line and 2,831 kcal on the mild gain line. On Sedentary (1.2) the same man gets 1,979 kcal of maintenance instead.

For a 30-year-old woman at 65 kg and 165 cm, the resting figure is 1,370 kcal. On Light (1.375) maintenance comes out at 1,884 kcal, with 1,609 kcal for mild loss and 2,159 kcal for mild gain.

  • Sedentary: BMR x 1.2
  • Light: BMR x 1.375
  • Moderate: BMR x 1.55 (the default)
  • Active: BMR x 1.725
  • Very active: BMR x 1.9

Turning a calorie number into a plan

Maintenance is a description, not an instruction. It is the intake that holds your current weight if the estimate is close, and the mild loss and mild gain lines are two small steps away from it rather than aggressive targets.

Once you have a calorie figure, the next question is what it is made of. The macro calculator splits a calorie target into grams of protein, carbohydrate, and fat, and the calorie deficit calculator takes a maintenance number and a deficit and returns a target intake with an estimated weekly change.

Review the number every few weeks. Maintenance falls as body weight falls, so a figure that was right at the start of a diet will overstate your needs a few kilograms later, and that alone can make progress appear to stall.

Tips

Getting a better result out of Calorie Calculator

Specific settings and thresholds, not general advice.

  • This is the Mifflin-St Jeor equation (10 x kg + 6.25 x cm - 5 x age, then plus 5 for men or minus 161 for women) multiplied by an activity factor from 1.2 to 1.9. Maintenance calories are the output, not a diet target.
  • The mild loss and gain lines move by 275 kcal, which is a quarter of a kilogram a week under the 7,700 calories per kilogram assumption (275 x 7 = 1,925, and 1,925 divided by 7,700 = 0.25).
  • Every part of this is a population average. Two people with identical inputs can have maintenance figures 200 to 300 kcal apart, which is why the number is a starting hypothesis you test against the scale rather than a measurement of you.
  • The activity dropdown is the weakest link, and people habitually pick a level too high. Sedentary (1.2) genuinely describes a desk job with no training. If in doubt, take the level below the one you were about to choose.
  • Recalculate as your weight changes. In this equation each kilogram lost takes 10 kcal off the resting figure and 10 times your activity factor off maintenance, so a diet that worked at the start will stall on its own if the number is never revisited.
  • This page shows maintenance and the two adjusted lines. If you want the resting figure on its own, the BMR calculator prints it, and the TDEE calculator shows both together.
Limits

What Calorie Calculator does not do

The honest boundary, so you do not lose time finding it yourself.

  • Metric only: kilograms, centimeters, and years. There is no imperial entry.
  • The activity factor is a five-step dropdown, not a measurement, and moving from 1.2 to 1.9 adds 70 percent of your resting figure to the result.
  • It does not model metabolic adaptation, so the number it gives you today will drift as your body changes.
  • It is an educational estimate, not medical or dietary advice. Calorie needs vary between individuals with identical inputs, and a doctor or registered dietitian should guide any real change to how you eat.
At a glance

Who Calorie Calculator is for

A quick way to understand who this helps, what it solves, and where it connects next.

Best fit

People tracking fitness, nutrition, and everyday health goals.

Ideal for

A quick, private health estimate without an account or app install.

FAQ

Common questions

Short answers for the questions people usually have before trying a utility like this.

How many calories should a 30-year-old man at 70 kg and 175 cm eat?

His maintenance estimate is 2,556 kcal a day at the Moderate activity level, from a resting figure of 1,649 kcal multiplied by 1.55. The mild loss line is 2,281 kcal and the mild gain line is 2,831 kcal. On Sedentary the maintenance figure drops to 1,979 kcal.

How many calories should a 30-year-old woman at 65 kg and 165 cm eat?

Her resting figure is 1,370 kcal, so maintenance at the Light activity level is 1,884 kcal a day. The mild loss line is 1,609 kcal and the mild gain line is 2,159 kcal. These are estimates, and individual needs vary.

What formula does the calorie calculator use?

Mifflin-St Jeor: 10 times weight in kilograms plus 6.25 times height in centimeters minus 5 times age in years, plus 5 for men or minus 161 for women, all multiplied by your activity factor.

Are maintenance calories what I should eat to lose weight?

No. Maintenance is what holds your current weight. To lose, you eat below it, and the mild loss line here shows one modest option: 275 kcal a day less, which works out to around a quarter of a kilogram a week under the usual energy assumptions.

Why does the tool show kcal rather than calories?

They are the same thing in everyday use. What a food label calls a calorie is a kilocalorie, so 2,000 calories and 2,000 kcal describe the same intake. The kcal label is just the more precise unit.

Which activity level fits a desk job with three gym sessions a week?

Light (1.375) or Moderate (1.55). Active (1.725) is for people who are physically busy most days on top of training, and Very active (1.9) is for people whose living is physical.

Why does this give a different number from my fitness watch?

A watch estimates from heart rate and movement and adds an exercise burn on top of a resting estimate, which double-counts if you then also pick a high activity level here. Trust neither exactly, and treat the scale over three weeks as the arbiter.

Why is the number lower than I expected?

Usually because you picked a lower activity level than the one you use elsewhere, or because Mifflin-St Jeor is more conservative than the older Harris-Benedict equation, which tends to overestimate. Mifflin-St Jeor is the one dietitians generally recommend.

Why does the male setting add 5 and the female setting subtract 161?

Those constants come from the regression Mifflin and St Jeor fitted to their measured subjects. The 166 calorie gap between them is the equation approximating the average difference in lean body mass at the same height, weight, and age.

Does it show my BMR too?

Not on this page. This one prints maintenance and the two adjusted lines. The BMR calculator gives the resting figure on its own, and the TDEE calculator shows the resting figure and the daily total side by side.

How long before I know if the number is right?

Two to three weeks of consistent eating and weighing. Daily weight is noisy because of water and food in transit, so what you want is the trend across weeks, not any single morning.

Can I enter pounds and feet?

No. The fields are kilograms, centimeters, and years. Divide pounds by 2.205 for kilograms, and multiply feet by 30.48 then add 2.54 per inch for centimeters.

Is the calorie calculator free?

Yes. It is completely free to use, with no signup, no account, and no paywall.

Does it stay local?

Yes. The height, weight, age, and other details you enter are processed entirely in your browser and never uploaded.

Are the results medical advice?

No. The output is a general estimate built from standard formulas and population averages, and real needs vary between individuals. For decisions about your health, diet, or training, check with a doctor or registered dietitian.

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