Body Mass Index (BMI)

Excel Formulas › Healthcare & Medical

All versions

BMI relates weight to height — weight in kilograms divided by height in meters squared (or a 703 factor for pounds and inches). A common screening number, easily built in a sheet.


Quick formula: BMI from kg and meters:
=weight_kg / height_m^2
Metric: kg over meters squared. Imperial: weight_lb / height_in^2 * 703.

The example

70 kg, 1.75 m.

AB
1ItemValue
2Weight 70 kg—
3Height 1.75 m→ 22.9

The formula

The formula:

=B2 / B3^2 // kg ÷ m²

How it works

How it works:

  1. Metric: weight_kg / height_m^2 — kilograms over meters squared.
  2. Imperial: weight_lb / height_in^2 * 703 — the 703 factor converts units.
  3. BMI is a screening ratio, not a body-composition measure — it ignores muscle vs fat.
  4. Map BMI to a category with a lookup (under 18.5, 18.5–24.9, 25–29.9, 30+).

Educational use only. These are general Excel formulas for learning spreadsheet techniques — not medical advice or a substitute for clinical judgment, professional guidelines, or verified dosing references. Always confirm calculations against authoritative sources and institutional protocols.

Try it: interactive demo

Live demo

Weight (kg) and height (m).

BMI:

Variations

Imperial (lb, in)

703 factor:

=weight_lb / height_in^2 * 703

Category lookup

Band the BMI:

=LOOKUP(bmi, {0;18.5;25;30}, {"Under";"Normal";"Over";"Obese"})

Target weight at a BMI

Solve back:

=target_bmi * height_m^2

Pitfalls & errors

Match units. Metric needs kg and meters; imperial needs the 703 factor with lb and inches.

Height in meters. 175 cm is 1.75 m — convert before squaring.

Screening only. BMI ignores muscle, frame, and distribution.

Practice workbook

📊
Download the free Body Mass Index (BMI) practice workbook
A BMI sheet with the imperial, category, and target-weight variants, plus 4 challenges with answers. No sign-up required.

Frequently asked questions

How do I calculate BMI in Excel?
Metric: =weight_kg / height_m^2. Imperial: =weight_lb / height_in^2 * 703. For 70 kg and 1.75 m, BMI is 22.9.
How do I show the BMI category?
Use a lookup: =LOOKUP(bmi, {0;18.5;25;30}, {"Under";"Normal";"Over";"Obese"}).
Why is my imperial BMI wrong?
You likely forgot the 703 factor, or mixed metric and imperial units. Use one system consistently.

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