TDEE Calculator - Maintenance Calories in lb & inches

Two steps: BMR, then activity

Your TDEE is built in two layers. First the calculator estimates basal metabolic rate, the energy your body uses just to stay alive at rest, with the Mifflin-St Jeor equation: BMR = 10 x weight (kg) + 6.25 x height (cm) - 5 x age + 5 for men, or - 161 for women. You enter pounds and inches; the tool converts them exactly (1 lb = 0.45359237 kg, 1 in = 2.54 cm).

Then it multiplies BMR by an activity factor: 1.2 sedentary, 1.375 lightly active, 1.55 moderately active, 1.725 very active, 1.9 extra active. The product is your TDEE, or maintenance calories.

Mifflin-St Jeor was published in 1990, and a 2005 review in the Journal of the American Dietetic Association found it the most reliable of the common prediction equations for healthy adults. It is still an estimate. Your real number could be a couple hundred calories either way.

Worked example: a moderately active man

35 years old, 180 lb, 5 feet 10 inches (70 in), trains 4 days a week. 180 lb is 81.65 kg and 70 in is 177.8 cm.

BMR = 816.5 + 1,111.3 - 175 + 5 = about 1,758 calories. At Moderate (1.55), TDEE is about 2,724 calories. The calculator then shows two targets: 2,224 to lose about 1 lb a week (TDEE - 500) and 2,974 to gain about half a pound a week (TDEE + 250).

Worked example: when the warning kicks in

45-year-old woman, 130 lb, 5 feet 2 inches (62 in), desk job, little exercise. BMR = 589.7 + 984.3 - 225 - 161 = about 1,188 calories. Sedentary (1.2) puts TDEE at about 1,426.

Subtract 500 and the loss target is about 926 calories. That is below 1,200, a commonly cited floor for women (1,500 for men), so the calculator flags it. Going that low without medical supervision makes it hard to get enough protein and micronutrients. For smaller, less active people the better levers are a smaller deficit, say 250 a day, and more daily movement, which raises TDEE instead of starving the target.

Why 500 calories is not a guaranteed pound

The 500-a-day rule comes from the old estimate that a pound of body fat holds about 3,500 calories: 500 x 7 = 3,500. It is a fine starting point and a poor long-term prediction.

Researchers at the NIH, led by Kevin Hall, built a dynamic model of body weight (published in The Lancet in 2011, and the basis of the NIH Body Weight Planner) showing that weight loss slows over time. As you get lighter, BMR drops and moving your body costs less energy, so the same intake produces a shrinking deficit. The static 3,500 rule overpredicts long-term loss. Recalculate your TDEE after every 10 to 15 lb lost.

Picking an activity level honestly

This is where most estimates go wrong. The multiplier covers your whole day, not just the gym. An hour of lifting does not cancel out nine hours at a desk and an evening on the couch.

A practical guide: Sedentary is an office job with no planned exercise. Light is an office job plus 1 to 3 workouts a week. Moderate is 3 to 5 solid sessions a week or a job with a lot of walking. Very Active is hard training most days or a physical job like construction. Extra Active is for athletes training twice a day or people doing heavy manual labor on top of workouts. If you are between two levels, pick the lower one. Overestimating is the more common error, and it is the one that stalls progress.

Calibrate with your own data

Treat the result as a first guess. Eat at the target for two to three weeks, weigh yourself each morning, and compare weekly averages, because daily weight swings 2 to 4 lb with water and salt. If the trend is flat when you expected loss, drop 100 to 200 calories. If you are losing faster than 1 percent of body weight a week, add some back. Your scale beats any formula. Not medical advice; talk to a doctor or registered dietitian if you are pregnant, managing a health condition, or have a history of disordered eating.