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Basal Metabolism Calculator

Basal metabolism calculator works out Basal metabolic rate and Resting metabolic rate (REE) from What to show, Units and Weight. The default figures on this page give total daily energy expenditure of 2,662.1 kcal/day; change any entry and the result, the working and the sources update together.

Total daily energy expenditure
2,662.1 kcal/day
BMR & TDEE Calculator
Basal metabolic rate
1,717.5 kcal/day
Resting metabolic rate (REE)
1,717.5 kcal/day
Activity multiplier
1.550
Basal metabolic rate
7,186 kJ/day
Total daily energy expenditure
11,138 kJ/day
Basal rate per kilogram
21.47 kcal/kg/day
Equation used
Mifflin-St Jeor (1990)
Worked out from Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO - A new predictive equation for resting energy expenditure in healthy individuals and 5 other sources.
BMR and RMR are different measurements; the predictive equations here were fitted to measured resting metabolic rate, so the same figure is reported for both.
The activity multipliers (1.2 to 1.9) are a long-standing convention rather than a measured constant for any individual. Track weight for two or three weeks and adjust.
Predictive equations estimate a population average and are typically within about 10 per cent of measured resting metabolic rate for most adults, with larger errors at the extremes of body size and in illness. They are not a substitute for indirect calorimetry and should not be used to manage a medical condition without clinical advice.

Your figures

Updates as you type
Only changes which figure is headlined; all three are always returned.
Metric uses kilograms and centimetres; US uses pounds with feet and inches; UK uses stones and pounds.
Body weight: kilograms (metric), pounds (US) or whole stones (UK).
Only used with UK stones-and-pounds: the pounds part, e.g. 11 st 4 lb is weight 11 and extra pounds 4.
Used when the unit system is metric.
Used when the unit system is US or UK.
The inches part of a feet-and-inches height.
These equations were fitted on adults; they are not valid for children.
Mifflin-St Jeor is the equation the Academy of Nutrition and Dietetics recommends for healthy adults. The lean-mass equations need a body-fat percentage.
Only used by the Katch-McArdle and Cunningham equations, which are driven by lean body mass.

How this is worked out

4 steps
  1. Mifflin-St Jeor (1990): BMR = 10 x 80 + 6.25 x 170 - 5 x 30 + 5
  2. BMR = 1717.5 kcal/day
  3. Activity: Moderately active - exercise 3-5 days a week, multiplier 1.55
  4. TDEE = 1717.5 x 1.55 = 2662.1 kcal/day
Daily calories at each activity leveltable
levelmultipliercalories
Sedentary - little or no exercise1.22,061
Lightly active - exercise 1-3 days a week1.3752,362
Moderately active - exercise 3-5 days a week1.552,662
Very active - hard exercise 6-7 days a week1.7252,963
Extra active - physical job or twice-daily training1.93,263

Its 5 worked examples are re-run on every release, last on 15 September 2026. What changed

Sources and references

6 sources

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Save it, change one figure, then compare the two

The calculation stays free. Save this scenario, adjust one assumption, save that too, and put them side by side to see exactly what the change costs you. A free account keeps 5 scenarios and 2 comparisons; Personal makes both unlimited and adds exports and private links. Nothing is saved unless you press Save.

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What the basal metabolism calculator calculates

Basal or resting metabolic rate from the Mifflin-St Jeor, Harris-Benedict, Katch-McArdle, Cunningham or Owen equations, and the total daily energy expenditure that follows from an activity level.

How to use this basal metabolism calculator

Enter What to show, Units, Weight and Extra pounds. Basal metabolic rate updates as you type, and “Use a worked example” loads checked figures you can adjust. Change one figure at a time to see what drives the result.

How the result is worked out

Open “How this is worked out” beside the result for the step-by-step calculation behind Basal metabolic rate, Resting metabolic rate (REE) and Total daily energy expenditure.

The method follows Mifflin MD, St Jeor ST, Hill LA, Scott BJ, Daugherty SA, Koh YO - A new predictive equation for resting energy expenditure in healthy individuals, Roza AM, Shizgal HM - The Harris Benedict equation reevaluated: resting energy requirements and the body cell mass, Harris JA, Benedict FG - A Biometric Study of Basal Metabolism in Man, Carnegie Institution of Washington Publication No. 279, Cunningham JJ - A reanalysis of the factors influencing basal metabolic rate in normal adults and Owen OE et al. - A reappraisal of caloric requirements in healthy women (1986) and in healthy men (1987).

Mifflin-St Jeor, 80 kg male, 180 cm, 30 years, moderately active example

With What to show: tdee, Units: metric, Weight: 80, Height: 180, the calculator returns Basal metabolic rate: 1780, Resting metabolic rate (REE): 1780, Total daily energy expenditure: 2759. This example is checked against an independent source in the test suite.

What you can compare

Change one input at a time to see how it affects Basal metabolic rate, Resting metabolic rate (REE) and Total daily energy expenditure. The inputs you can vary are What to show, Units, Weight, Extra pounds, Height and Height (feet).

Understanding Basal metabolic rate, Resting metabolic rate (REE) and Total daily energy expenditure

Predictive equations estimate a population average and are typically within about 10 per cent of measured resting metabolic rate for most adults, with larger errors at the extremes of body size and in illness. They are not a substitute for indirect calorimetry and should not be used to manage a medical condition without clinical advice.

Results are general information, not financial, tax, legal, medical or engineering advice. Check any decision that matters with a qualified professional.

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Copy this code into any page. The calculator appears with the figures currently entered, sizes itself to fit, and a small credit line links back here. Free, no account, no ads inside it, no tracking of your readers. Set your own figures and fixed fields; Personal removes the credit line, sets your colour and shows you which sites use it.

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Frequently asked questions

How do I calculate my basal metabolism?

Basal or resting metabolic rate from the Mifflin-St Jeor, Harris-Benedict, Katch-McArdle, Cunningham or Owen equations, and the total daily energy expenditure that follows from an activity level. Open “How this is worked out” beside the result to see each step for your own figures.

Can I just eat my BMR to lose weight?

Basal or resting metabolic rate from the Mifflin-St Jeor, Harris-Benedict, Katch-McArdle, Cunningham or Owen equations, and the total daily energy expenditure that follows from an activity level. On the figures this page opens with — weight 80, height 180 cm and age 30 years — the total daily energy expenditure is 2,662.1 kcal/day. Put your own figures in their place and the working updates beside the result.

Is a 1400 basal metabolic rate good?

It needs What to show, Units, Weight, Extra pounds, Height and Height (feet). Nothing else is required, and the figures stay in your browser.

What is my basal metabolic rate for my age?

Basal or resting metabolic rate from the Mifflin-St Jeor, Harris-Benedict, Katch-McArdle, Cunningham or Owen equations, and the total daily energy expenditure that follows from an activity level. On this page it is computed from What to show, Units and Weight and shown as Basal metabolic rate, Resting metabolic rate (REE) and Total daily energy expenditure.

What information do I need for the basal metabolism calculator?

You need What to show, Units, Weight, Extra pounds, Height, Height (feet), Height (inches) and Age. The page opens with default figures that give total daily energy expenditure of 2,662.1 kcal/day, so you can see the scale before entering your own.

What does this basal metabolism calculator show?

It shows Basal metabolic rate, Resting metabolic rate (REE), Total daily energy expenditure, Activity multiplier, Basal rate per kilogram, Lean body mass, Equation used and Daily calories at each activity level, with the working and any warnings for your entries.

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