Calorie Calculator (TDEE)

TDEE starts with your Basal Metabolic Rate (BMR), the calories your body burns at complete rest, then multiplies it by an activity factor to account for movement and exercise throughout the day. The BMR Formula dropdown lets you pick which of 3 real formulas calculates that number: Mifflin-St Jeor, generally considered the most accurate for the average person; the Revised Harris-Benedict equation, an older formula some people prefer to compare against; or Katch-McArdle, covered in the next section, which needs your body fat percentage.

For the default 70kg, 170cm, 30-year-old male at Moderately Active: Mifflin-St Jeor gives a BMR of 1,617.5, and multiplying by the 1.55 activity factor gives a maintenance level of about 2,507 calories per day. The Revised Harris-Benedict equation for the same person gives a slightly higher BMR of about 1,672, and a maintenance level of about 2,591.

Both Mifflin-St Jeor and Harris-Benedict estimate lean body mass indirectly from age and gender, which works well on average but can be noticeably off for someone leaner or more muscular than typical. If you know your body fat percentage, from calipers, a smart scale, or a DEXA scan, select Katch-McArdle from the BMR Formula dropdown, which reveals a Body Fat % field: BMR equals 370, plus 21.6 times your lean body mass in kg (your weight times one minus your body fat as a decimal).

For the same 70kg example at 15% body fat, Katch-McArdle gives a BMR of about 1,655. Unlike Mifflin-St Jeor and Harris-Benedict, Katch-McArdle doesn't use age or gender at all since real, measured lean mass already captures what those variables were only estimating.

Body Mass Index (BMI) is your weight divided by your height squared, a quick, widely used screening number for whether your weight falls in a typical range for your height. It's shown here because it's a natural companion question to "how many calories do I need," not because it feeds into the calorie math above, BMI and TDEE are calculated completely independently of each other.

The protein, carbohydrate, and fat grams shown here use a balanced 30% protein, 40% carbohydrate, 30% fat split of your maintenance calories, a reasonable general-purpose starting point for most people, not a plan tailored to a specific goal.

The activity multiplier is the most common place people overestimate their own number. "Moderately active" means real structured exercise 3-5 days a week, not just a generally busy schedule; a desk job with no regular workouts is Sedentary even if the day feels tiring. When unsure, it's safer to pick the lower of two options and adjust upward later based on real results, since overestimating activity is the most common reason a calculated calorie target doesn't match reality.

A 500 calorie daily deficit or surplus targets roughly 0.5kg (1lb) of change per week, a pace generally considered sustainable without excessive muscle loss. Deficits larger than 1,000 calories per day risk losing muscle along with fat and can lower your metabolism over time, making the weight harder to keep off. TDEE estimates are typically accurate within about 10-15%; track your weight for two weeks at your calculated maintenance level and adjust up or down based on what actually happens, rather than treating the first number as final.

The weekly schedule below shows one common alternative to eating the exact same calorie total every day: calorie cycling (sometimes called "zigzag" dieting). It keeps weekends at your full maintenance level and lowers weekdays just enough that the week's real total still matches your weight-loss target exactly, which can make a deficit easier to stick to without changing how much weight you're actually aiming to lose. This is one common way to structure the cycle, not the only one; a steady daily deficit works just as well mathematically; use whichever you can actually stick to.