TDEE Calculator

Background.

This TDEE calculator estimates your Total Daily Energy Expenditure — the number of calories your body burns in a typical 24-hour period once you account for everything from basic metabolic function to your training, your job, and the small fidgety movements you make without thinking. It works in two steps. First it computes your basal metabolic rate (BMR) using the Mifflin-St Jeor equation, the predictive formula that the American Dietetic Association evidence analysis in 2005 ranked as the most accurate of the commonly used resting-energy-expenditure equations in healthy non-obese and obese adults. Then it multiplies that BMR by the activity factor you select — 1.2 for sedentary up to 1.9 for extra active — to produce a daily calorie target. The result is the calorie intake at which, on average, you neither gain nor lose body mass over time. It is the anchor point that every deliberate cut, lean bulk, body-recomposition phase, and metabolic-adaptation conversation is measured against.

TDEE is built from four physiological components, and it is worth understanding all of them because they each respond to different inputs. The largest is BMR, typically 60–70% of the total. BMR is the cost of keeping you alive at rest — heart, brain, kidneys, liver, basic cellular maintenance — and it scales mainly with fat-free mass, which is why heavier and more muscular people have higher BMRs. The second component is the thermic effect of food (TEF), the calories your body spends digesting, absorbing, and storing what you eat. TEF is usually 8–12% of total intake and varies by macronutrient: protein has the highest thermic effect at roughly 20–30% of its calories, carbohydrates around 5–10%, and dietary fat the lowest at 0–3%. The third is exercise activity thermogenesis (EAT), the calories you burn during deliberate training. The fourth, and the one most people underestimate, is non-exercise activity thermogenesis (NEAT) — walking to the train, taking the stairs, gesturing, fidgeting, standing rather than sitting. James Levine's classic NEAT research at Mayo Clinic showed that NEAT can vary by as much as 2,000 calories a day between two adults of the same body size, and it is the single biggest reason that two people on the same diet and the same gym programme can end up with very different body-composition outcomes. The activity multiplier in this calculator bundles EAT and NEAT together, which is convenient but also the part of the estimate that carries the most uncertainty for any given individual.

Two questions follow immediately from any TDEE number. How do you use it to cut, and how do you use it to bulk? The conventional answer for fat loss is to eat in a calorie deficit of 10–25% below TDEE — typically 300–500 kcal/day for a modest cut, 500–750 kcal/day for a more aggressive one — knowing that a deficit of roughly 7,700 kcal is equivalent to one kilogram of body fat. The 0.5 kg per week guideline (a 500 kcal/day deficit) is the rule of thumb dietitians cite most often because it preserves lean mass better than aggressive cuts when paired with adequate protein (1.6–2.2 g per kg of body weight) and resistance training. For lean bulking, a calorie surplus of 5–15% above TDEE, typically 200–400 kcal/day, gives a gain rate of roughly 0.25–0.5% of body weight per week — fast enough to add muscle measurably, slow enough that the gain is not dominated by fat.

Beyond the simple arithmetic, TDEE varies — sometimes substantially — from one day to the next, and that day-to-day noise is normal. A long run, an extra hour of standing at a wedding, a stressful work day that pushes resting heart rate up, a cold morning, even a heavy meal can each shift the actual number burned by several hundred calories. That is why nutritionists track diet and weight in weekly averages rather than daily snapshots. The other source of variation that catches people out is adaptive thermogenesis: as you lose weight, your BMR drops both because you have less mass to maintain and because the body downregulates resting expenditure beyond what the mass change alone would predict, by anywhere from 5% to 15% in many studies. This is the classic 'diet plateau' — the same calorie intake that produced steady loss for eight weeks suddenly stops working, because TDEE has fallen toward the new intake. The fix is not necessarily to cut harder; it is often to recompute TDEE at the new body weight, take a diet break at maintenance for a week or two, and then resume a smaller deficit.

The Mifflin-St Jeor equation this calculator uses was published by M.D. Mifflin and S.T. St Jeor in 1990 in the American Journal of Clinical Nutrition based on indirect calorimetry measurements in 498 healthy adults, and it has been the workhorse predictive equation in clinical practice ever since because it predicts measured resting metabolic rate within ±10% in roughly 70% of healthy adults — the highest accuracy of any commonly used non-Harris-Benedict equation in the Frankenfield 2005 review.

The number this page returns is therefore an evidence-based starting estimate, not a measured value. If precise expenditure matters — for example in elite sports, in clinical malnutrition assessment, or in metabolic research — indirect calorimetry with a metabolic cart is the gold standard. For everyone else, the Mifflin TDEE estimate plus two to three weeks of weight tracking against a fixed calorie intake will tell you, empirically, how close the equation got for your specific physiology, and you can then adjust intake by a few hundred calories up or down to find your true maintenance number.

What is tdee calculator?

Total Daily Energy Expenditure (TDEE) is the total number of calories an adult burns in 24 hours, accounting for resting metabolism, the cost of digesting food, deliberate exercise, and incidental non-exercise activity. TDEE is the calorie intake at which body mass is held constant over time, which is why it is also called 'maintenance calories'. It is built from four components: basal metabolic rate (BMR), which accounts for roughly 60–70% of the total and represents the cost of keeping organs and cellular processes running at rest; the thermic effect of food (TEF), roughly 8–12% of intake, which is the calories spent processing what you eat; exercise activity thermogenesis (EAT), the calories burned in deliberate training; and non-exercise activity thermogenesis (NEAT), the calories burned in walking, standing, fidgeting, and routine movement — often the most variable component and the one that can differ by up to 2,000 kcal/day between adults of similar size. In practice TDEE is estimated by predicting BMR from a regression equation — the Mifflin-St Jeor formula (1990) is the current standard, validated in the Frankenfield 2005 review as more accurate than Harris-Benedict, WHO/FAO, or Owen across healthy adult populations — and then multiplying by an activity factor between 1.2 (sedentary) and 1.9 (extra active). The output is an estimate, not a measurement. Indirect calorimetry remains the gold standard for true resting expenditure, but Mifflin-St Jeor predictions land within ±10% of measured values in approximately 70% of healthy adults, which makes the equation sufficient for setting realistic calorie targets for cutting, bulking, or recomposition without specialised equipment.

How to use this calculator.

1. 01Select your biological sex. The Mifflin-St Jeor equation uses +5 for male and −161 for female; these constants come from the original 1990 regression and reflect the average difference in body composition between sexes at the same height and weight.
2. 02Enter your age in whole years. Age reduces predicted BMR by 5 kcal/day per year because resting expenditure declines gradually with age, primarily as lean mass declines.
3. 03Enter your current weight in kilograms. If you weigh in pounds, divide by 2.2046 to convert (for example 170 lb ÷ 2.2046 ≈ 77.1 kg). Use a recent morning weight, ideally an average of the last 3–7 days to smooth out daily fluctuations.
4. 04Enter your height in centimetres. If you know your height in inches, multiply by 2.54 (for example 5'9" = 69 in × 2.54 = 175.3 cm).
5. 05Pick the activity level that matches your typical week. Be honest. Most people who work desk jobs and train 3–4 times a week fall in the 1.375 (lightly active) or 1.55 (moderately active) band, not 1.725. Overstating activity is the single most common reason a calculated TDEE is too high.
6. 06Read the TDEE number. This is your estimated daily maintenance calories. To lose weight, eat 10–25% below it (typically 300–750 kcal/day deficit). To gain lean mass, eat 5–15% above it (typically 200–400 kcal/day surplus). Track weight as a 7-day rolling average for at least 2–3 weeks before adjusting — daily noise will mislead you.
7. 07Read the BMR number underneath. Do not eat below your BMR for any length of time without clinical supervision; deep caloric restriction below resting expenditure tends to accelerate lean-mass loss and metabolic adaptation.

The formula.

The calculator implements the Mifflin-St Jeor equation for BMR and then multiplies by an activity factor to estimate TDEE. The BMR formula in metric units is BMR = (10 × weight in kg) + (6.25 × height in cm) − (5 × age in years) + s, where the sex constant s is +5 for males and −161 for females. The four coefficients (10, 6.25, 5, and the sex constant) come from the multiple-regression fit Mifflin and colleagues published in the American Journal of Clinical Nutrition in 1990 using indirect-calorimetry measurements on 498 healthy adults aged 19–78 with body-mass indices from 17 to 42. The TDEE step is BMR × activity factor, where the five canonical activity factors are 1.2 (sedentary — desk job, little or no exercise), 1.375 (lightly active — light exercise 1–3 days/week), 1.55 (moderately active — moderate exercise 3–5 days/week), 1.725 (very active — hard exercise 6–7 days/week), and 1.9 (extra active — very hard daily exercise or a physically demanding job on top of training). These multipliers originate in the Harris-Benedict tradition and are documented in the Frankenfield 2005 ADA evidence-analysis review as well as the FAO/WHO/UNU 2001 report on human energy requirements. Worked example for a 30-year-old male, 70 kg, 175 cm, moderately active: BMR = (10 × 70) + (6.25 × 175) − (5 × 30) + 5 = 700 + 1093.75 − 150 + 5 = 1648.75 kcal/day. TDEE = 1648.75 × 1.55 = 2555.56 kcal/day. The calculator returns 1649 kcal/day BMR and 2556 kcal/day TDEE (rounded for display). For a female of the same age, weight, and height the BMR drops by 166 kcal (the difference between +5 and −161): BMR = 1482.75 kcal/day, TDEE at 1.55 = 2298.26 kcal/day.

A worked example.

Frequently asked questions.

References& sources.

1. [1]Mifflin MD, St Jeor ST, Hill LA, Daugherty BJ, Koh YO — A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition 51(2):241–247 (1990). The original derivation of the Mifflin-St Jeor BMR equation from indirect-calorimetry measurements in 498 healthy adults.
2. [2]Frankenfield D, Roth-Yousey L, Compher C — Comparison of predictive equations for resting metabolic rate in healthy nonobese and obese adults: a systematic review. Journal of the American Dietetic Association 105(5):775–789 (2005). The American Dietetic Association evidence analysis that ranks Mifflin-St Jeor as the most accurate of the commonly used predictive REE equations.
3. [3]Institute of Medicine — Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (2005). National Academies Press. The U.S. DRI reference for total energy expenditure equations, activity multipliers, and protein recommendations.
4. [4]FAO/WHO/UNU Expert Consultation — Human energy requirements. FAO Food and Nutrition Technical Report Series 1, Rome (2001/2004). The international reference report establishing physical-activity-level (PAL) categories and multipliers from 1.4 (sedentary) to 2.4 (vigorous) and validating them against doubly-labelled water measurements.
5. [5]Thomas DT, Erdman KA, Burke LM — Position of the Academy of Nutrition and Dietetics, Dietitians of Canada, and the American College of Sports Medicine: Nutrition and Athletic Performance. Medicine & Science in Sports & Exercise 48(3):543–568 (2016). The joint ACSM/AND/DC position stand on energy availability, calorie targets, protein intake, and macronutrient timing for athletes.
6. [6]Levine JA — Non-exercise activity thermogenesis (NEAT). Best Practice & Research Clinical Endocrinology & Metabolism 16(4):679–702 (2002). The foundational review of NEAT as a component of TDEE, documenting the up-to-2,000 kcal/day inter-individual variation that the activity multiplier attempts to capture.
7. [7]Rosenbaum M, Leibel RL — Adaptive thermogenesis in humans. International Journal of Obesity 34(S1):S47–S55 (2010). Peer-reviewed review of the metabolic adaptation that drives weight-loss plateaus, quantifying the 5–15% reduction in REE beyond what mass loss alone predicts.