Height Converter

Height is the distance from the floor to the top of your head when you stand straight. Countries record it in different units, so converting between them is a common task. This converter turns one entered height into all five units at once.

What Height Conversion Measures

This tool changes the unit, not the height. 5 ft 10 in and 177.8 cm are the same height written two ways. It does not measure you or judge your height.

The Formula

The whole conversion rests on one exact number. The inch has been defined as exactly 25.4 millimeters since July 1, 1959¹.

Centimeters = (feet x 12 + inches) x 2.54

Inches = centimeters / 2.54

How This Calculator Computes Your Result

Choose the unit you are starting from, then type your height. You can also paste text like 5'10" or 5 ft 10 in and the tool reads it for you. Everything is converted to centimeters first, and nothing is rounded until the final step, which keeps the maths exact. Centimeters show to 1 decimal, meters to 3 decimals, millimeters to the nearest whole number and inches to 1 decimal. A tape measure view rounds to the nearest quarter inch. If the inches field is 12 or more, it rolls into feet, so 5 ft 14 in becomes 6 ft 2 in.

What Your Result Means

The result is your height in five units. Here are common heights for quick checking.

How to Measure Correctly

A converter is only as good as the number you give it. Clinics and national health surveys use a stadiometer, a flat wall-mounted ruler with a sliding headpiece².

- Take off your shoes and hair accessories.

- Stand with heels together and the back of your head, shoulder blades, buttocks and heels touching the wall.

- Look straight ahead with your head level. Technically this is the Frankfort plane, an imaginary line from the ear canal to the lower edge of the eye socket that should sit parallel to the floor.

- Stand as tall as you can and take a deep breath. This straightens the spine.

- Have someone lower the headpiece flat onto your head and read the number to the nearest 0.1 cm.

- Measure in the morning if you can. Height changes during the day.

Why You Are Taller in the Morning

Your spine compresses slightly under the weight of daily activity. In one study of 34 adults, height dropped by about 7 mm on average between two measurements taken at different times of day³. If you want your tallest, most repeatable number, measure soon after you get up.

Self-Reported Height Is Usually Too High

Most people guess their height rather than measure it, and the guess tends to run high. In US national survey data (NHANES, 2001 to 2006), men overreported their height by an average of 1.22 cm (0.48 in) and women by 0.68 cm (0.27 in)⁴. The gap grew with age. Men aged 80 and over overreported by about 3.9 cm⁴. If you are entering a height from memory, a quick measurement can give a more useful starting number.

Why Countries Use Different Units

The United States uses feet and inches in daily life, and so do some other countries, while most of the world uses centimeters. In the US, the metric system has been legal since 1866 and became the preferred system for trade and commerce in 1988, but customary units are still common in everyday speech⁵. BMI, a common use of height, is defined with height in meters⁶.