TDEE Calculator
Estimate total daily energy expenditure by scaling BMR with an activity factor.
What this tool does
This calculator estimates Total Daily Energy Expenditure by multiplying a Basal Metabolic Rate by an activity factor from 1.2 (sedentary) to 1.9 (very active). Enter a BMR in kilocalories, choose a factor, and it returns the daily total in both kilocalories and kilojoules, the weekly figure, and where that factor sits against the physical activity level bands published by FAO/WHO/UNU. The 1.2 to 1.9 ladder is a long-standing fitness convention rather than a consensus figure, and the comparison is there so you can see how far apart the two are.
Formula Used
Disclaimer
This calculator is for educational and informational purposes only. It does not provide medical, nutritional, or training advice. Results are mathematical estimates and may not reflect individual circumstances. Consult a qualified coach, registered dietitian, medical professional, or physiotherapist for personal guidance.
How the TDEE Calculator works
The tool multiplies a Basal Metabolic Rate by an activity factor to estimate Total Daily Energy Expenditure. Enter a BMR in kilocalories and pick one of five factors from 1.2 to 1.9. The result is shown in kilocalories and kilojoules, since food labelling uses one or the other depending on where you are, along with the weekly total and a comparison against published activity-level bands.
The formula
TDEE = BMR × activity factor. Working the default, 1,700 kcal at a factor of 1.55 gives 1,700 × 1.55 = 2,635 kcal per day, which is 2,635 × 4.184 = 11,025 kJ, or 18,445 kcal across a week. The arithmetic is a single multiplication; everything interesting is in where the factor comes from.
Where the 1.2 to 1.9 ladder actually comes from
It is a convention in wide use across fitness calculators, not a figure drawn from the consensus energy-requirement reports. That distinction matters, because those reports classify the very same quantity differently. FAO/WHO/UNU express 24-hour energy needs as a multiple of BMR and call it the physical activity level, or PAL, and their Table 5.3 gives three bands: 1.40 to 1.69 for a sedentary or light activity lifestyle, 1.70 to 1.99 for an active or moderately active one, and 2.00 to 2.40 for a vigorously active one. The report also states that PAL values sustainable long term by free-living adult populations run from about 1.40 to 2.40 (FAO/WHO/UNU, 2004, section 5.3).
Line the two up and they do not agree. This calculator’s Sedentary (1.2) and Light (1.375) both sit below 1.40, the floor FAO reports for free-living adults, and its top rung of 1.9 lands inside FAO’s middle band rather than its vigorous one. A factor of 1.55, labelled Moderate here, is FAO’s sedentary-or-light category. The tool now names the comparable band beside your result rather than leaving the mismatch unstated. The Institute of Medicine takes a third approach again, building activity coefficients into its estimated energy requirement equations rather than publishing a single multiplier ladder (Institute of Medicine, 2005).
Where this method is most accurate
A multiplier applied to BMR lines up best with measured expenditure in adults holding a stable body weight on a consistent routine. It drifts during rapid weight change, illness, or when activity swings day to day. The preset factors assume typical occupational and recreational loads, and individual variation in non-exercise activity thermogenesis is large enough to move the answer by several hundred kilocalories in either direction. Treat the output as a starting estimate to be corrected against real weight data over two or three weeks, not as a measurement.
Bringing your own BMR
The calculator asks for BMR rather than computing it, which keeps it independent of any one equation. If you do not have a figure, the Mifflin-St Jeor and Harris-Benedict calculators on this site both produce one from height, weight, age and sex, and the Katch-McArdle version uses lean mass instead if you know your body fat percentage. Indirect calorimetry measures it directly and is what the equations are approximating.
What this tool does not do
It does not measure energy expenditure, adjust for metabolic adaptation, or account for variation in the thermic effect of food. It does not set calorie targets for body-composition goals, assess health, or replace individual assessment by a registered dietitian or exercise physiologist. The result is arithmetic on the numbers you supply.
Disclaimer
This tool is for educational and informational purposes only. It is not medical, nutritional, or training advice. Consult a qualified healthcare or fitness professional before making decisions based on calculator outputs. Individual metabolic responses vary, and no formula can capture every physiological variable.
Questions
- What is the difference between BMR and TDEE?
- BMR is the energy your body uses at complete rest to keep running. TDEE adds everything on top: exercise, occupational movement, fidgeting and other non-exercise activity thermogenesis, and the energy cost of digesting food. The activity factor is the bridge, scaling BMR up by an amount meant to represent all of that.
- Where do the 1.2 to 1.9 factors come from?
- They are a convention widely reproduced across fitness calculators rather than a published consensus figure, which is why the tool now shows how each one compares to the FAO/WHO/UNU physical activity level bands. Those bands run 1.40 to 1.69 for a sedentary or light lifestyle, 1.70 to 1.99 for a moderately active one, and 2.00 to 2.40 for a vigorous one, so the two systems label the same numbers quite differently.
- Why does the result say my factor is below the FAO floor?
- Because the 1.2 and 1.375 options fall under 1.40, and FAO/WHO/UNU report that sustainable long-term physical activity levels for free-living adult populations start around 1.40. A figure below that is closer to bed rest than to a desk job with a commute. If you selected Sedentary and the answer looks low against what you actually eat at stable weight, that gap is a large part of why.
- Can TDEE change over time?
- Yes. It moves with body weight, lean mass, activity habits, age, and metabolic adaptation to a sustained deficit. Losing weight lowers both BMR and the cost of moving the smaller body. A rise in training volume or a change of job can move you a band. Recalculating every few months, and checking the estimate against actual weight trend, keeps it honest.
- Why does this calculator ask for BMR instead of working it out?
- So that it stays independent of any one BMR equation. Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle all give different answers from the same person, and indirect calorimetry gives another. This site has calculators for all three equations, and whichever figure you trust can be fed in here.
- Why is the result shown in kilojoules as well?
- Because food labels use kilojoules across the European Union, Australia and New Zealand, and kilocalories elsewhere. One kilocalorie is 4.184 kilojoules, so the default 2,635 kcal is 11,025 kJ. Having both means you can compare the estimate against whichever figure is printed on the packet in front of you.
- What if my activity level varies day to day?
- The factors assume a consistent average. Some people calculate two figures, one for training days and one for rest days, and eat accordingly; others pick the factor nearest their weekly average and let it even out. Wearable estimates give finer resolution but carry their own error, particularly for non-step activity.
Sources & Methodology
TDEE = BMR × activity factor, with factors of 1.2, 1.375, 1.55, 1.725 and 1.9. That ladder is a fitness convention rather than a figure from the consensus energy-requirement literature. FAO/WHO/UNU (2004, Table 5.3) classify the same quantity, 24-hour energy expenditure as a multiple of BMR, which they term physical activity level (PAL), as 1.40–1.69 sedentary or light, 1.70–1.99 active or moderately active, and 2.00–2.40 vigorously active, with about 1.40 the lower bound sustainable by free-living adults. The result names the comparable PAL band. Kilojoules use 1 kcal = 4.184 kJ.
- › FAO/WHO/UNU. Human Energy Requirements: Report of a Joint FAO/WHO/UNU Expert Consultation. Rome; 2004. Section 5.3, classification of lifestyles by physical activity level.
- › FAO/WHO/UNU. Human Energy Requirements, full report contents.
- › Institute of Medicine. Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids. National Academies Press; 2005.
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