Activity levels: the PAL table
Physical activity level (PAL) is total energy expenditure over 24 hours divided by BMR, so BMR times PAL gives TDEE. The 2001 FAO/WHO/UNU expert consultation sorted lifestyles into three categories and gave each one a range of PAL values, not a single number. The last column shows what each range means in calories for the man in the worked example, whose resting energy is 1,799 kcal a day.
| Lifestyle | PAL range | Example man, kcal a day |
|---|---|---|
| Sedentary or light activity | 1.40-1.69 | 2,518-3,040 |
| Active or moderately active | 1.70-1.99 | 3,058-3,579 |
| Vigorous or vigorously active | 2.00-2.40 | 3,597-4,317 |
- Sedentary or light activity. Work that does not demand much physical effort, no long walks, motor transport, no regular exercise or sport, and leisure time spent mostly sitting or standing. The report’s example is an office worker in a city who only occasionally does anything physically demanding.
- Active or moderately active. Work that is not strenuous but uses more energy than a sedentary job, or a sedentary job combined with regular moderate to vigorous activity. The report’s examples include masons and construction workers.
- Vigorous or vigorously active. Strenuous work or strenuous leisure activity for several hours, regularly. The report’s examples are farm laborers working without machinery who also walk long distances, and women with non-sedentary jobs who swim or dance for an average of two hours a day.
Three more points from the report help with the choice:
- One hour a day of moderate to vigorous exercise, such as jogging or running, cycling, aerobic dancing or various sports, can raise a person’s average PAL from 1.55 to 1.75. That moves someone with a sedentary job into the moderately active range.
- In a pooled analysis of 411 adults aged 18 to 64, mostly from affluent countries and described as having a predominantly sedentary Western lifestyle, the most common PAL was 1.60.
- PAL values above 2.40 are difficult to maintain over a long period.
The report’s own worked examples for the three lifestyles come out at PAL 1.53, 1.76 and 2.25.
How it works
Total daily energy expenditure is the energy your body uses in 24 hours. The FAO/WHO/UNU report on human energy requirements says that for healthy, well-nourished adults the energy requirement is equivalent to total energy expenditure: it is the food energy that balances what is spent and keeps body size and composition where they are. That is why TDEE is also called maintenance calories.
The calculator gets there in two steps.
- Resting energy. Basal metabolic rate (BMR) is the energy the body uses lying at rest, fasted and relaxed. It can be measured only in a laboratory, so it is usually predicted from sex, weight, height and age. This page uses the Mifflin-St Jeor equation unless you choose another. The papers call the figure resting energy expenditure. Calculators label it BMR, and so does this one.
- Activity. Resting energy is multiplied by a physical activity level (PAL). The report sorts lifestyles into three PAL ranges. You pick one, and the calculator shows the low end, the high end and the middle of the range.
The result is an estimate for a typical adult with your numbers, not a measurement of you. This page stops at maintenance: it does not set calorie targets above or below it.
The formula
Mifflin-St Jeor, kcal a day
men = 10 × kg + 6.25 × cm
− 5 × age + 5
women = 10 × kg + 6.25 × cm
− 5 × age − 161
Revised Harris-Benedict
men = 88.362 + 13.397 × kg
+ 4.799 × cm
− 5.677 × age
women = 447.593 + 9.247 × kg
+ 3.098 × cm
− 4.330 × age
Katch-McArdle
BMR = 370 + 21.6 × fat-free kg
fat-free kg
= kg × (1 − body fat ÷ 100)
TDEE = BMR × PAL
kg = lb ÷ 2.20462
cm = inches × 2.54Weight is in kilograms, height in centimeters and age in years. PAL is the physical activity level. The FAO/WHO/UNU ranges are 1.40 to 1.69 for sedentary or light activity lifestyles, 1.70 to 1.99 for active or moderately active lifestyles and 2.00 to 2.40 for vigorous or vigorously active lifestyles.
Worked example
A 30-year-old man who weighs 180 lb and is 5 ft 11 in tall, with a sedentary or light activity lifestyle.
- Weight: 180 ÷ 2.20462 = 81.65 kg. Height: 5 ft 11 in is 71 inches, and 71 × 2.54 = 180.34 cm.
- Mifflin-St Jeor: 10 × 81.65 + 6.25 × 180.34 − 5 × 30 + 5 = 1,798.6, so about 1,799 kcal a day at rest.
- The lifestyle range is PAL 1.40 to 1.69: 1,798.6 × 1.40 = 2,518 and 1,798.6 × 1.69 = 3,040 kcal a day.
- The middle of the range is PAL 1.545: 1,798.6 × 1.545 = 2,779 kcal a day.
For the same man the revised Harris-Benedict equation gives 1,877 kcal a day at rest, and at 15% body fat the Katch-McArdle equation gives 1,869.
The three BMR equations
- Mifflin-St Jeor (1990). Built on 498 healthy people aged 19 to 78, 251 men and 247 women, of whom 264 were of normal weight and 234 obese. Their resting energy was measured by indirect calorimetry, which works it out from the oxygen a person breathes in and the carbon dioxide they breathe out. It uses sex, weight, height and age.
- Revised Harris-Benedict (1984). Harris and Benedict published their equations in 1919 from measurements of 239 people. Roza and Shizgal recalculated them with those people plus 98 from Benedict’s later studies, who covered a wider range of ages: 168 men and 169 women in all. It uses sex, weight, height and age.
- Katch-McArdle. This one works from fat-free mass alone, so it needs a body fat percentage and takes no account of sex, height or age. Calculators name it after the exercise physiology textbook by McArdle, Katch and Katch, which research papers cite for it. The same equation is the general prediction equation Cunningham proposed in 1991 after reviewing earlier studies, where it explained 65 to 90% of the variation in resting energy.
Mifflin and colleagues reported that the original 1919 Harris-Benedict equations overestimated measured resting energy by 5% in their sample. For the example man the 1919 equation gives 1,889 kcal a day, the revised one 1,877 and Mifflin-St Jeor 1,799.
The 1.2 to 1.9 activity multipliers
Many TDEE calculators multiply BMR by one of five numbers: 1.2, 1.375, 1.55, 1.725 and 1.9, with labels that run from sedentary to extra active. The five are evenly spaced, 0.175 apart. We looked for the study they come from and could not trace them to a primary source, so this page does not use them. It uses the FAO/WHO/UNU ranges above, which can be read in the report itself.
The lowest of the five, 1.2, is also below those ranges: the report puts the PAL values that free-living adults can sustain over a long period at about 1.40 to 2.40.
To compare with a calculator that uses them, choose My own PAL value and type its multiplier. For the example man, 1.2 gives 2,158 kcal a day and 1.55 gives 2,788.
How far to trust the number
- An equation for resting energy describes the average of the people it was built on. In a 2005 systematic review, Mifflin-St Jeor predicted resting metabolic rate to within 10% of the measured value in more people than the other equations it was compared with, and the review still found noteworthy errors when it is applied to individuals.
- Roza and Shizgal give 95% confidence limits of ±213 kcal a day for their men’s equation and ±201 kcal for the women’s, about 14% of the estimate.
- The activity step is wider still. Each lifestyle covers a range of PAL values: for the example man the sedentary or light range alone runs from 2,518 to 3,040 kcal a day, a span of 522 kcal.
- The FAO/WHO/UNU report predicts BMR with its own equations, from body weight by age group. Multiplying a Mifflin-St Jeor figure by its PAL ranges combines two sources, which makes the result an approximation.
- Katch-McArdle depends on the body fat figure you enter, and any error in that figure carries through. The body fat calculator shows how large that error can be for a tape measure estimate.
- In the report’s definition, BMR times PAL equals total energy expenditure for adult men and for women who are not pregnant or breastfeeding.
Questions
What is TDEE?
Total daily energy expenditure: the energy your body uses in 24 hours, in kilocalories. It is estimated as resting energy (BMR) times a physical activity level. For a 30-year-old man of 180 lb, 5 ft 11 in with a sedentary or light activity lifestyle, this page gives 2,518 to 3,040 kcal a day, with 2,779 in the middle.
What is the difference between BMR and TDEE?
BMR is the energy used at complete rest. TDEE is everything: BMR plus the energy for digesting food and for all movement through the day. The FAO/WHO/UNU report puts BMR at about 45 to 70 percent of total energy expenditure in adults, and says physical activity is the most variable part. This page shows both numbers: BMR is the first figure under the result.
What are maintenance calories?
The calories that match what you use, so that body weight stays about the same over time. In the FAO/WHO/UNU report’s words, for healthy, well-nourished adults the energy requirement is equivalent to total energy expenditure. This page estimates that number and stops there. To split it into protein, carbohydrate and fat, use the macro calculator.
Which BMR equation is the most accurate?
A 2005 systematic review in the Journal of the American Dietetic Association compared the equations most used in clinical practice and found Mifflin-St Jeor the most reliable: it predicted resting metabolic rate to within 10% of the measured value in more nonobese and obese people than any other equation, with the narrowest error range. That is why it is the default here. The same review notes that older adults and some ethnic groups were underrepresented in the studies, and that measuring resting energy by indirect calorimetry is the way to remove the estimation error.
Why does this calculator not use 1.2, 1.375 and 1.55?
Because we could not trace those multipliers to a primary source. They are evenly spaced numbers from 1.2 to 1.9. This page uses the lifestyle ranges of the FAO/WHO/UNU report on human energy requirements instead: 1.40 to 1.69 for sedentary or light activity, 1.70 to 1.99 for active or moderately active and 2.00 to 2.40 for vigorous or vigorously active. You can still type any multiplier under My own PAL value.
Which activity level should I pick if I lift weights?
Go by your whole day, not only the gym. The report describes the sedentary or light range as a job with little physical effort and no regular exercise or sport. As one example, it says an hour a day of moderate to vigorous exercise can raise a person’s average PAL from 1.55 to 1.75, which is the difference between the sedentary and the moderately active range. The activity level table has the report’s descriptions of all three.
Does TDEE go down with age?
In these equations, yes. Mifflin-St Jeor subtracts 5 kcal a day for each year of age, so at the same weight and height a 40-year-old is estimated 50 kcal a day lower than a 30-year-old. The revised Harris-Benedict equation subtracts 5.677 kcal a year for men and 4.330 for women. Katch-McArdle has no age term: it follows fat-free mass.
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Sources
- Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO. A new predictive equation for resting energy expenditure in healthy individuals. American Journal of Clinical Nutrition. 1990;51(2):241-247.
- Roza AM, Shizgal HM. The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass. American Journal of Clinical Nutrition. 1984;40(1):168-182. Table 3, equations 3 and 6.
- Cunningham JJ. Body composition as a determinant of energy expenditure: a synthetic review and a proposed general prediction equation. American Journal of Clinical Nutrition. 1991;54(6):963-969.
- Molina-Luque R, Carrasco-Marín F, Márquez-Urrizola C, Ulloa N, Romero-Saldaña M, Molina-Recio G. Accuracy of the resting energy expenditure estimation equations for healthy women. Nutrients. 2021;13(2):345. Table of equations: Katch-McArdle as 370 + 21.6 × fat-free mass.
- FAO/WHO/UNU. Human energy requirements: report of a joint FAO/WHO/UNU expert consultation, Rome, 17-24 October 2001. FAO Food and Nutrition Technical Report Series 1. Rome; 2004. Chapter 5, energy requirements of adults: Tables 5.1 and 5.3 and section 5.3.
- FAO/WHO/UNU. Human energy requirements (as above). Chapter 2, principles and definitions: energy requirement, total energy expenditure, basal metabolic rate and physical activity level.
- 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. 2005;105(5):775-789.
- National Institute of Standards and Technology. Guide for the Use of the International System of Units (SI), Special Publication 811, Appendix B.9: 1 inch = 2.54 cm and 1 lb = 0.4535924 kg.