TDEE Calculator

What TDEE actually measures

TDEE stands for total daily energy expenditure: every calorie your body burns in a full day, including the energy you would burn lying still, the energy you spend moving around, and the energy used to digest and store the food you eat. It is the number that decides whether your weight goes up, down or nowhere.

Four components add up to that total. Resting metabolic rate is the largest slice, usually 60% to 70% of the day for someone with a desk job. The thermic effect of food adds roughly 10%. Non-exercise activity - walking, fidgeting, stairs, housework - is the most variable part and often the difference between two people of the same size. Structured training sits on top, and for most people it is a smaller slice than they expect.

How the TDEE formula works

This calculator uses Mifflin-St Jeor for resting energy because it is the equation most dietitians reach for and the one that holds up best across body sizes: 10 x weight in kilograms + 6.25 x height in centimetres - 5 x age, plus 5 for men and minus 161 for women. The result is your resting burn for a full 24 hours, not per hour.

That resting figure is then multiplied by an activity factor to cover everything you do on top of lying still. The multipliers are 1.2 for a desk job with little exercise, 1.375 for light training one to three times a week, 1.55 for three to five sessions, 1.725 for six or seven, and 1.9 for hard training twice a day. Choosing the factor honestly matters more than any other input on this page: overstating your activity is the single most common reason a calorie target feels too generous.

Reading your TDEE result

The result table gives you four numbers worth understanding. Maintenance is the intake that keeps your weight where it is. The cutting line is 20% below maintenance, a deficit most people can hold for two to three months without their training falling apart. The bulking line is 10% above maintenance, a surplus small enough that a good share of the gain is muscle rather than fat. The protein figure is 1.6 to 2.0 grams per kilogram, the range that consistently preserves muscle during a deficit.

Treat maintenance as a band rather than a point. Day-to-day energy burn swings by 100 to 300 calories with steps, stress and sleep, so a single day above or below the line means nothing. Compare weekly averages, and only change the target after two weeks of consistent eating and morning weigh-ins.

A worked example

A 30-year-old man at 178 cm and 75 kg training three to five times a week: resting energy is 10 x 75 + 6.25 x 178 - 5 x 30 + 5, which comes to 1,718 kcal a day. Moderate activity multiplies that by 1.55, giving a maintenance figure of about 2,662 kcal.

A 20% cut puts him at roughly 2,130 kcal a day, a deficit of 532 kcal. Across a week that is about 3,700 kcal, or a little over one pound of body weight. A 10% surplus instead gives about 2,930 kcal and a slower, more controlled gain. Change the inputs above and the same arithmetic runs on your own numbers.

How accurate is a TDEE estimate?

Published validation work puts Mifflin-St Jeor within about 10% of measured resting energy for most healthy adults, which sounds reassuring until you apply it to a 2,600 kcal maintenance figure: a 10% error is 260 calories a day, or roughly two pounds a month. The activity multiplier adds its own error because two people who both train three times a week can differ by thousands of daily steps.

Wearable estimates are not a way out of this. Heart-rate based devices commonly read 10% to 30% away from laboratory measurement, and they are least reliable during strength training and interval work. The practical answer is to treat the calculator as the starting point and the scale as the referee: eat the target for two weeks, average your morning weights, then adjust by 100 to 200 calories in the direction the trend tells you.

Common mistakes that skew the number

Most bad TDEE results come from four habits rather than from the equation. Overstating activity is the biggest: if you train three times a week but sit for nine hours a day, you are not 'very active'. Rushing a deficit is the second - dropping to 1,200 calories to speed things up costs muscle, wrecks training quality and usually ends in a rebound.

The third is treating the estimate as a measurement and giving up after four days. The fourth is double counting: the activity factor already includes your training, so logging a session on top and 'eating back' another 400 calories counts the same work twice.

• Choosing an activity level you have not actually been doing for the past month.
• Cutting harder than 20% to 25% below maintenance without supervision.
• Judging progress on daily weights instead of a weekly average.
• Adding back exercise calories the activity multiplier already covered.

What to do with the number

Pick one target, run it for two weeks and keep everything else stable: same training, same weigh-in routine, same logging method. If your weekly average is falling by 0.5% to 1% of body weight, change nothing. Falling faster, add 100 to 200 calories. Barely moving after two consistent weeks, remove 100 to 200 calories or add 2,000 daily steps before cutting food further.

Recalculate after every 5 to 7 kg of weight change, because a smaller body burns less at rest and moves less cheaply. The estimate is meant to be revised, not obeyed.

Frequently asked questions