Five calculations you can check by hand
A reproducible practice set for resting energy, activity scenarios, BMI, energy units, and macro totals.
Example 1: a resting-energy estimate
Use a fictional adult aged 40, weighing 80 kg and measuring 180 cm, with the male coefficient. The weight term is 800. The height term is 1,125. The age term is 200. Combine them as 800 + 1,125 − 200 + 5 = 1,730 kcal/day. Enter those values in the BMR tool to reproduce the result.
Now change only the coefficient to female. The constant changes from +5 to −161, so the result is 1,564. This exercise illustrates a feature of the published equation; it does not establish the actual resting expenditure of a particular person.
Examples 2 and 3: activity and BMI
For a purely arithmetic daily-energy example, take 1,730 and multiply by 1.2. The result is 2,076. At 1.55, it becomes 2,681.5, displayed as 2,682. Notice that the activity calculation begins with an existing estimate and adds an assumed factor.
For BMI, use the same 80 kg and 180 cm. Convert height to 1.8 m, then square it to get 3.24. Calculate 80 ÷ 3.24 = 24.691358…. The display rounds to 24.69. This arithmetic uses only height and weight; the adult tool’s age field checks eligibility for the category system.
Examples 4 and 5: energy and macros
For an energy-unit example, convert 500 kcal to kJ: 500 × 4.184 = 2,092 kJ. Divide 2,092 by 4.184 to reverse the conversion. Unlike a prediction equation, this example changes units using a defined conversion factor; it is not trying to infer someone’s physiology.
For a macro example, enter 25 g protein, 40 g carbohydrate, and 12 g fat. The components are 100, 160, and 108 kcal. Their sum is 368 kcal. These invented gram amounts are practice inputs, not recommended targets. A real label may use additional energy factors beyond the simplified calculation.
Build your own check without guessing
Choose simple inputs and write your expected result before using the tool. Change one input at a time, leaving everything else fixed. Doubling an energy amount should double its converted amount. Doubling every macro gram value should double the total. Increasing weight changes BMI differently from increasing height because height is squared.
Record the unrounded answer and the displayed answer separately. If there is a mismatch, trace the intermediate terms rather than repeatedly pressing calculate. A reproducible example helps identify an error. It does not prove that a health estimate is clinically accurate for everyone who can enter valid numbers.