Feet and Inches to Meters — Height for Formulas
American height comes in two parts: feet and inches, said together. Metric height is one number. The conversion adds them separately — feet × 0.3048, plus inches × 0.0254 — because a foot is exactly 0.3048 m and an inch exactly 0.0254 m by NIST definition. Enter both parts:
Height
—m
Why the formula refuses feet
Nearly every clinical calculation that uses height uses it in meters or centimeters, and there is a structural reason: feet and inches are two numbers in different bases, and you cannot square them, divide by them, or take a square root of them without merging them first.
- Body mass index is defined as kilograms divided by meters squared. The American version multiplies by 703 precisely to fold this conversion in, as the BMI calculator does.
- Body surface area, the number that governs chemotherapy and burn-fluid dosing, takes height in centimeters in the Mosteller formula.
- Growth charts for children plot centimeters against age.
- Lung function reference values, the “percent predicted” on a spirometry report, are computed from equations written in centimeters.
So converting is not a formatting preference. It is the step that makes the height usable, and it has to happen before any squaring, not after.
Common heights in meters
| Feet and inches | Meters | Centimeters |
|---|---|---|
| 5 ft 0 in | 1.52 m | 152.4 cm |
| 5 ft 2 in | 1.57 m | 157.5 cm |
| 5 ft 4 in | 1.63 m | 162.6 cm |
| 5 ft 6 in | 1.68 m | 167.6 cm |
| 5 ft 8 in | 1.73 m | 172.7 cm |
| 5 ft 9 in | 1.75 m | 175.3 cm |
| 5 ft 10 in | 1.78 m | 177.8 cm |
| 6 ft 0 in | 1.83 m | 182.9 cm |
| 6 ft 2 in | 1.88 m | 188.0 cm |
| 6 ft 4 in | 1.93 m | 193.0 cm |
The half inch you rounded away
Almost nobody is a whole number of inches tall, and almost everybody reports one. That habit is the largest source of error on this page — much larger than any conversion factor.
Take someone who measures 5 ft 8.5 in and calls it 5 ft 9 in. In meters that is 1.740 against 1.753 — just over a centimeter. Run both through BMI at 168 lb and you get 25.2 for the real height and 24.8 for the rounded one. Four tenths of a point, and it happens to straddle the line between healthy weight and overweight. That is where people care, and it is exactly where the rounding is least forgivable.
Two habits fix it. Measure barefoot with your heels, back and head against a wall, with something flat laid level on top of your head — not a hand, which tilts. And carry the half inch through the conversion instead of dropping it at the start.
Height also shrinks over a day, by roughly half an inch from morning to night as the spinal discs compress. If you are comparing this year’s number with last year’s, compare measurements taken at the same time of day.
The rest of the conversion
Weight travels with height into almost every one of these formulas, and pounds to kg covers that side. If you only need inches without the feet, use inches to cm. And once you have meters and kilograms, the metric BMI calculator takes them directly.
This content is informational and does not replace evaluation by a health professional.
Frequently asked questions
What is 5 ft 9 in in meters?
1.75 m, or 175.3 cm. The arithmetic is 5 × 0.3048 plus 9 × 0.0254, which gives 1.524 plus 0.2286.
How many centimeters is one foot?
Exactly 30.48 cm. NIST defines the foot as precisely 0.3048 m, so the twelve inches inside it are exactly 2.54 cm each.
How do I go from meters back to feet and inches?
Divide the meters by 0.3048. The whole part is the feet; multiply what is left by 12 for the inches. From 1.70 m: 5.577 ft, so 5 feet and 0.577 × 12, about 7 inches.
Does an inch of height really change my BMI?
Yes, by about 0.4 points for an adult of average build — more than the difference between two weigh-ins. Height is squared in the formula, so it moves the result faster than weight does.
Sources
- NIST Guide to the SI, Appendix B.9 — Conversion Factors by Kind of Quantity
- Assessing Your Weight and Health Risk — National Heart, Lung, and Blood Institute (NHLBI)
Written by Lucas Silva · Reviewed by Lucas Silva · Updated on August 13, 2026