Calorie Calculator

What is BMR?

Basal Metabolic Rate (BMR) is the number of calories your body burns at complete rest, just keeping your organs running, before any movement, digestion, or exercise is added on top. Every target on this page starts from a BMR estimate, then multiplies it by an activity-level factor to reach Total Daily Energy Expenditure (TDEE), which is what is tdee really means: your full day's burn, not just your resting rate. This calculator offers a choice of three widely published formulas for that first BMR step:

Mifflin-St Jeor (1990)

This is the formula most dietitians default to today for the general population, and it is this calculator's own default.

Revised Harris-Benedict (1984 revision of the 1919 original)

A harris benedict calculator like this one tends to run slightly higher than Mifflin-St Jeor for the same person.

Katch-McArdle

Unlike the other two, it needs a body-fat percentage, which makes it more work to use accurately, but it tends to be more accurate for people noticeably more or less muscular than average, since it is not working from total weight alone.

Worked comparison. A 25-year-old, 180cm, 80kg man: Mifflin-St Jeor gives a BMR of 1,805 kcal/day. Revised Harris-Benedict gives 1,882.02 kcal/day, about 77 kcal higher. Katch-McArdle, assuming a reasonably lean 15% body fat (lean mass 68kg), gives 1,838.80 kcal/day, in between the other two. None of the three is simply wrong; they are different published equations, validated on different populations, and a roughly 80 kcal spread across all three for the identical person is a completely normal amount of disagreement, not a sign that one of them made an error.

From BMR to TDEE

This is the maintain figure every other target on this page is built from, using whichever activity-level multiplier matches how much you move in a normal day.

Official and well-known calculators from bodies like NASM, the Mayo Clinic, and the USDA's MyPlate.gov calorie calculator all use some version of this same BMR-times-activity-multiplier logic. The U.S. National Institutes of Health additionally offers a more advanced Body Weight Planner, which models how metabolism itself gradually adapts during a long diet rather than assuming a single fixed number throughout, a level of detail beyond what a static formula like the three above, or a static dri calculator for that matter, can capture on its own.

Calorie counting as a means to lose weight

The deficit math behind weight loss is simple in principle: roughly 3,500 kcal of stored energy corresponds to about one pound (0.45 kg) of body weight, so a 500 kcal/day deficit (about 3,500 kcal a week) tends to produce roughly one pound of loss a week, and a 250 kcal/day deficit tends to produce roughly half that. How many calories to gain a pound works exactly the same way in reverse, as a surplus. How many calories in a lb, or in a lb of fat more precisely, comes back to that same 3,500 figure, and 1 lb fat how many calories is simply the same question asked the other way around.

It is worth sanity-checking a goal against this math before committing to it. Someone hoping to lose 20 pounds in 3 months is targeting 20 × 3,500 = 70,000 kcal of total deficit. Divided across roughly 90 days, that is about 778 kcal/day, well beyond even this calculator's standard 500 kcal/day pace, and a deficit that size is far more likely to be unsustainable, or unsafe without supervision, than a slower, steadier plan using the mild or standard targets above.

Zigzag calorie cycling

Zigzag calorie cycling keeps the same weekly total calories as eating one flat number every day, but spreads it unevenly: a few lower days and a few higher days, rather than an identical amount 7 days in a row. The schedule above builds this automatically from whichever loss or gain target you pick, with 4 lower days and 3 higher days that mathematically average back to exactly that target across the week, and a second pattern using the same 7 numbers on different days, so the specific rhythm can vary from week to week. The appeal is mostly practical rather than metabolic: some people find it easier to stick to a plan that allows a higher-calorie day around a weekend or a workout, rather than treating every single day identically.

How many calories do you need, according to the calorie calculator?

How many calories does an average person consume a day varies enormously by country, age, sex, and activity level, which is exactly why a personalised calculator like this one is more useful than a single quoted national average. Daily calories for men tend to land higher than for women at the same age and activity level, mainly because BMR scales with lean body mass and men typically carry more of it, which is also why the Katch-McArdle formula above can narrow that gap for two people of very different body composition. Someone specifically bulking, in the gym sense of the word, is really just looking at this calculator's gain columns: a bulking calculator and a bulking calorie calculator are asking the exact same question as the "Gain" rows above, just with fitness-specific framing.

If your actual question is about calories burned through a specific activity rather than a daily target, a walking calorie calculator, a calories burned walking calculator, or a MET calculator (which rates activities by how many multiples of resting metabolism they burn) are the more direct tools; on this site, that is the Calories Burned Calculator, not this page, which focuses on your overall daily target rather than a single workout.

Calories: different kinds and their effects

Not every kcalorie on a label comes from the same source, and the source matters for more than just the number. Converting grams to calories uses a fixed energy density for each macronutrient: carbohydrate and protein both provide about 4 kcal per gram, fat provides about 9 kcal per gram, more than double, and alcohol provides about 7 kcal per gram. A gram of fat is not "worse" in some moral sense, it is simply more energy-dense, which is exactly why fatty foods make it easier to overshoot a calorie target without necessarily eating a large volume of food. A rough calorie density table for some common foods, in kcal per 100 grams, illustrates the same point:

A portion is rarely 100 grams, so scale the figure to what you eat: a food at 200 kcal per 100 grams supplies 500 kcal in a 250 gram portion. Weighing food is the quickest way to remove guesswork from a calorie target, and even a basic kitchen scale beats estimating by eye.

The food energy converter above the zigzag schedule handles the unit side of the same topic: a nutrition label's "Calories" is really kcalories, and outside the U.S. many labels lead with kilojoules (kJ) instead, where 1 kcal equals roughly 4.184 kJ. It also converts to watt-hours and BTU, the same energy unit this site's own BTU Calculator uses, since a calorie and a BTU are simply two different units measuring the identical underlying quantity: energy. None of this replaces detailed food tracking; apps such as NutritionCalc Plus exist specifically to log what was actually eaten, whereas this calculator only estimates the target to eat toward.