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CM to Inches Converter

Convert centimeters to inches instantly — or reverse. Get feet and inches breakdown for heights, plus a full reference table.

cm
Result
66.93 in = 5 ft 6.93 in
Reverse Converter
in
170.00 cm

Conversion Formula

inches = cm × 0.3937
cm = inches × 2.54

Quick heights

CM to Inches Conversion Table

Centimeters (cm) Inches (in) Feet + Inches

Understanding Centimeters and Inches

The centimeter and the inch are both units used to measure length, but they belong to two different measurement systems that have divided the world for centuries. The centimeter is part of the metric system, now officially known as the International System of Units (SI), which is used by nearly every country on the planet. The inch belongs to the imperial system, a legacy measurement framework that persists primarily in the United States, with partial use in Canada and the United Kingdom.

Understanding how to convert between the two is not just useful for travelers — it's a daily necessity for anyone who works with international clothing brands, medical data, construction drawings, or fitness tracking. A person who is 170 cm tall might need to know they are 5 feet 6.93 inches in a country using imperial units. A product listed at 12 inches wide translates to exactly 30.48 cm for a metric buyer.

The exact relationship between the two units is fixed by international definition: 1 inch = 2.54 centimeters exactly. This was agreed upon in 1959 by the United States, United Kingdom, Canada, Australia, New Zealand, and South Africa. Before that date, the inch had slightly different values in different countries — the US inch was 25.4000508 mm while the UK inch was 25.399977 mm. The 1959 international agreement resolved this discrepancy once and for all.

How to Convert CM to Inches

The conversion from centimeters to inches is straightforward once you know the factor. Since 1 inch equals 2.54 cm, to go from centimeters to inches you divide by 2.54 — or equivalently, multiply by 0.393701.

CM to Inches

Multiply your cm value by 0.393701. Example: 50 cm × 0.393701 = 19.685 inches.

Inches to CM

Multiply your inches value by 2.54. Example: 20 inches × 2.54 = 50.8 cm.

CM to Feet + Inches

Convert cm to total inches first, then divide by 12. The integer part is feet, the remainder is inches.

Quick Mental Math

Roughly: 1 inch ≈ 2.5 cm. So 100 cm ≈ 40 inches. For accuracy, always use 2.54.

Step-by-Step Example: Converting 175 cm to Feet and Inches

Let's walk through converting 175 cm to feet and inches:

Height Conversions: Common CM Values in Feet and Inches

Height is probably the most common reason people need to convert between centimeters and inches. In the United States and several other countries, height is almost always expressed in feet and inches. When applying for jobs, signing up for fitness apps, or filling in a medical form, you'll frequently encounter height fields expecting imperial values.

Here are the most searched height conversions:

Note that when people say they are "5'9"" or "6 foot", they are typically rounding to the nearest whole inch. In practice, 175 cm is often rounded to 5'9" rather than the more precise 5'8.90".

CM vs Inches: Which Countries Use Which?

The metric system, with centimeters as its length subunit, is the official measurement standard in 195 countries. Every member of the European Union, all of Asia, Africa, South America, Australia, and New Zealand uses the metric system in everyday life, education, commerce, and science.

The imperial system with inches is officially used as the primary system in only three countries:

Canada is a unique case: officially metric since 1971, Canadians use centimeters for official purposes, but many still informally describe heights in feet and inches and distances in miles. You'll often see dual labeling on Canadian products.

United Kingdom officially adopted metric decades ago, but road signs are still in miles and many British people still give their height in feet and inches and weight in stones and pounds — a cultural persistence that survives official policy.

Impact on Daily Life

The divide between metric and imperial creates friction in several real-world situations. Engineers working on international projects must constantly convert between the two systems. In 1999, NASA's Mars Climate Orbiter was lost because one team used metric units while another used imperial — a $327 million lesson in why conversions matter. Medical professionals in the US must convert patients' self-reported metric heights and weights to imperial for insurance forms and vice versa. Fashion and clothing sizes are a daily conversion challenge for international online shoppers, as European sizes use centimeters for body measurements while American sizes use inches.

Clothing Sizes and CM to Inches

If you shop internationally online, you'll encounter measurement systems that use centimeters for body measurements while the clothing labels show sizes in inches. Here are the most common clothing measurements you'll need to convert:

Men's Waist Sizes

Inseam Length (Jeans)

Shoe Sizes (Foot Length)

Always check the specific brand's size chart, as there can be slight variations between manufacturers. Using the actual centimeter body measurement and comparing to the brand's cm size guide is always more accurate than guessing from size numbers alone.

History of the Inch and Centimeter

The inch has ancient roots. The word "inch" derives from the Latin uncia, meaning "one-twelfth part" — specifically one-twelfth of a foot. In the Anglo-Saxon tradition, an inch was defined as the length of three barleycorns placed end to end. King Edward II of England standardized it in 1324 as exactly three grains of barley, dry and round, placed end to end.

The centimeter has a much shorter but more systematic history. It emerged from the French metric system, developed during the French Revolution in the 1790s. The meter was defined as one ten-millionth of the distance from the equator to the North Pole along the meridian passing through Paris. A centimeter (from Latin centum, meaning hundred) is simply one hundredth of a meter — making the metric system inherently decimal and much easier to work with mathematically.

Today, both units are defined in terms of the speed of light. The meter is the distance light travels in a vacuum in 1/299,792,458 of a second, and the inch is exactly 0.0254 meters — no ambiguity, no approximation.

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Frequently Asked Questions

1 centimeter equals exactly 0.393701 inches. This is derived from the exact definition that 1 inch = 2.54 cm, so 1 ÷ 2.54 = 0.393701. For quick mental math, you can approximate 1 cm as roughly 0.4 inches, but for precise conversions always use 0.393701.
Multiply your cm value by 0.393701 to get total inches. Then divide by 12 — the whole number is feet, the remainder is inches. For example: 170 cm × 0.393701 = 66.93 total inches. 66.93 ÷ 12 = 5 feet with 6.93 inches remaining. So 170 cm = 5 ft 6.93 in.
5 feet = 152.4 cm exactly. To calculate: 5 feet × 12 = 60 inches, then 60 × 2.54 = 152.4 cm. If you mean 5 feet 0 inches, that's 152.4 cm. 5 feet 6 inches = 167.64 cm, and 5 feet 10 inches = 177.8 cm.
170 cm = 5 feet 6.93 inches. This is often rounded to 5'7" in everyday usage. The exact calculation: 170 × 0.393701 = 66.929 total inches. 66.929 ÷ 12 = 5 feet with 6.929 inches left over.
Almost every country in the world uses centimeters as part of the metric system — including all of Europe, Asia, Africa, Australia, and South America. The United States is the main country that still primarily uses inches for everyday measurements. Canada officially uses metric, but many Canadians still informally describe heights in feet and inches. The UK is officially metric but retains many imperial habits culturally.
The exact conversion: inches = cm × 0.393701 (or equivalently cm ÷ 2.54). The reverse: cm = inches × 2.54. The factor 2.54 is the exact, internationally defined value — 1 inch = 2.54 cm exactly, established by international agreement in 1959 and unchanged since.