bmr calculator — the complete guide
This guide covers the BMR Calculator end to end: what it does, what each field means, the formula behind it, worked examples, and the limits of the result. If you only need the answer, enter your numbers and read the headline. If you want to trust the answer, read on.
The inputs, in order, are the numbers the formula needs — no more, no less. Enter them in the units shown beside each field, and check the units before you move on: a unit slip is the single most common cause of a wrong result with any calculator.
Worked example: A 30-year-old man, 70 kg, 175 cm: BMR = 10 × 70 + 6.25 × 175 − 5 × 30 + 5 = 1,649 kcal a day. The formula behind that example is: Men (Mifflin-St Jeor): BMR = 10 × weight + 6.25 × height − 5 × age + 5; women use − 161 instead of + 5. Run those numbers through the calculator and confirm the result matches. Then try your own numbers, one field at a time, so you can see which input moves the answer most.
The limits: BMR is the energy your body uses at rest. Daily needs are higher, because activity is added on top — BMR alone is not a calorie target. Within those limits, the calculator is exact arithmetic on the inputs you gave it. Outside them, it is still exact arithmetic — but on a question you did not mean to ask.
Frequently asked questions
What does this guide cover that the tool page does not?
The same calculation, explained in full: every field, the formula, worked examples, common mistakes, and the limits of the result.
Where do I find the tool itself?
Through the button at the end of this guide, or from the site’s tool list. The guide and the tool use the same formula and the same worked example.
Is the result a promise or a guarantee?
Neither. It is arithmetic on the inputs you entered. Real outcomes vary with rates, prices and circumstances the calculator cannot see.
More guides on the BMR Calculator
- How to use the BMR Calculator — step by step
- BMR Calculator explained with worked examples
- BMR Calculator formula — how it actually works
- BMR Calculator for beginners — start here
- Common mistakes people make with the BMR Calculator
- BMR Calculator vs doing it by hand — which is faster?
- How to get an accurate result from the BMR Calculator
- BMR Calculator for students — with examples
- BMR Calculator for homeowners and DIYers
Enter your age, weight, height and sex to see your basal metabolic rate in calories a day.