TDEE Calculator
Estimate your total daily energy expenditure and the calorie intake for losing, maintaining or gaining weight at a chosen rate.
How to use this calculator
- 1Enter your details and pick an activity level — deliberately choose the lower option if you are between two.
- 2Select your goal and how quickly you want to change.
- 3Track your weight over two to three weeks and adjust: if it is not moving as predicted, the activity multiplier is the thing to change.
How the calculation works
TDEE = BMR × Activity factor Target = TDEE ± (weekly rate × 7,700 / 7)- BMR
- Basal metabolic rate from the Mifflin–St Jeor equation
- Activity factor
- 1.2 (sedentary) to 1.9 (extremely active)
- 7,700
- Approximate kcal stored per kilogram of body mass
The 7,700 kcal-per-kilogram figure (3,500 per pound) is a planning convention, not a physical constant. Real weight change is slower than it predicts over long periods, because metabolic rate falls as body mass does.
Activity factors are broad categories. Two people who both describe themselves as "moderately active" can differ by 400 kcal a day.
Worked example
A 30-year-old male, 175 cm, 75 kg, moderately active, losing 0.5 kg a week
- 1.BMR = 10(75) + 6.25(175) − 5(30) + 5 = 1,699 kcal.
- 2.TDEE = 1,699 × 1.55 = 2,633 kcal.
- 3.A 0.5 kg weekly loss needs a deficit of 0.5 × 7,700 ÷ 7 = 550 kcal a day.
- 4.Target intake = 2,633 − 550 = 2,083 kcal.
Result: About 2,083 kcal a day
The four things TDEE adds together
Total daily energy expenditure is not one measurement but the sum of several physiologically distinct processes, each of which behaves differently and responds to different things.
- Basal metabolic rate (BMR) — energy spent at complete rest, typically the largest single share of the total — see the BMR Calculator for how it is estimated.
- Thermic effect of food (TEF) — the energy cost of digesting, absorbing and processing what is eaten. Protein has the highest thermic cost of the three macronutrients, fat the lowest.
- Non-exercise activity thermogenesis (NEAT) — everything from fidgeting and posture to walking around and doing chores — unplanned movement that varies enormously between individuals and is a major reason two people with identical jobs can have very different calorie needs.
- Exercise activity thermogenesis (EAT) — deliberate structured exercise — training sessions, sport, planned cardio — which for most non-athletes is the smallest of the four components, despite being the one people focus on most.
Why activity is bundled into one broad multiplier
Rather than estimating NEAT, TEF and EAT separately — which would need data almost nobody tracks — TDEE calculators borrow a shortcut from the same family as the Harris–Benedict equation: a single activity multiplier applied to BMR, ranging roughly from 1.2 for a sedentary lifestyle to 1.9 for very heavy training or physical work. It is a coarse approximation by design, and the categories are wide enough that two people who would both describe themselves as “moderately active” can genuinely differ by several hundred calories a day.
Turning TDEE into a deficit or surplus
Converting a target rate of weight change into a daily calorie adjustment relies on a planning convention — roughly 7,700 kcal stored per kilogram of body mass, about 3,500 kcal per pound — that traces back to mid-20th-century energy-balance research. It is a useful rule of thumb, not a precise physical constant: real bodies do not lose or gain weight in a perfectly straight line, because resting metabolism tends to fall somewhat as sustained calorie restriction continues, a phenomenon generally referred to as adaptive thermogenesis.
That is why a TDEE estimate works best as a starting hypothesis rather than a fixed prescription — the standard practical approach is to eat at the calculated target for a couple of weeks, track actual weight change, and adjust the number based on what happens rather than trusting the formula indefinitely.
Where the estimate tends to go wrong
Most of the error in a real-world TDEE estimate comes from two sources that have nothing to do with the arithmetic: activity level is usually rated too generously, and self-reported food intake is reliably underestimated, sometimes substantially, in nutrition research. Both errors push in the same direction — toward apparently unexplained weight gain or slower-than-predicted loss — which is why tracking trends over time is more informative than trusting a single calculated number.
What this assumes, and where it stops
Assumptions
- The Mifflin–St Jeor equation predicts your BMR accurately, within its usual ±10%.
- Your chosen activity multiplier reflects your real weekly activity.
- Weight change follows the 7,700 kcal per kilogram convention.
Limitations
- Prediction error compounds: an inaccurate BMR estimate multiplied by an uncertain activity factor can be 300–500 kcal away from your true expenditure.
- Metabolic adaptation means a deficit becomes less effective over time; targets need revisiting every few weeks.
- Not appropriate for pregnancy, breastfeeding, children, athletes in heavy training blocks, or anyone managing a medical condition without professional guidance.
Common questions
How accurate is a TDEE calculator?
Treat it as a starting hypothesis, not a measurement. The BMR equation carries around ±10% error, and the activity multiplier is a broad category. The reliable method is to eat at the estimate for two to three weeks, track your weight, and adjust from what actually happens.
Why is my weight not dropping at the predicted rate?
Usually one of three things: the activity level is overestimated, intake is underestimated (portion sizes and cooking oil are the usual culprits), or you are seeing water-weight noise. Weight also fluctuates by a kilogram or more day to day, so judge progress on a weekly average rather than a single reading.
How big should a calorie deficit be?
Commonly 10–20% below maintenance, which for most people means 0.25–0.5 kg a week. Larger deficits lose more lean mass, are harder to sustain, and increase the metabolic adaptation that makes further loss slower.
Sources
- Dietary reference intakes calculator — US Department of Agriculture
- Healthy weight loss guidance — US Centers for Disease Control and Prevention
Formula and content last reviewed on .
Results are estimates for information only, not professional advice.
Related calculators
Tools people commonly use alongside the tdee calculator.