Inches to CM Converter
Convert inches to centimeters instantly. Type a value in the field below and the equivalent number of centimeters appears as you type. The formula is a single multiplication by 2.54, which is the exact number of centimeters in one international inch — a relationship fixed by treaty rather than measured, so every result you see is exact.
Inches → Centimeters
Exact conversion. No sign-up. Works offline after the page loads.
Note: Negative values are converted mathematically. Physical lengths are normally positive.
The inches to centimeters formula
centimeters = inches × 2.54
The value 2.54 is not an approximation. In 1959, an international agreement between the United States, the United Kingdom, Canada, Australia, New Zealand, and South Africa fixed the international inch at exactly 2.54 centimeters. Because this is a legal definition rather than a measured quantity, the conversion has no uncertainty — 12 inches is exactly 30.48 centimeters, not approximately.
To reverse the calculation and go from centimeters back to inches, divide by 2.54. The multiplication and the division are exact inverses of one another, so converting a value in one direction and then back always returns the original number, subject only to the normal limits of floating-point representation inside a computer.
This direction — inches to centimeters — is the one where the arithmetic is exact by construction. Every other length conversion on this site involves a division that produces a repeating decimal for most inputs. This one does not. The multiplying factor is itself a terminating decimal, so multiplying any terminating decimal input by 2.54 produces a result that terminates as well. That makes this converter the most precise of the five on the site, in the sense that no rounding whatsoever is required to express most results.
Worked examples
Each example below shows the arithmetic step by step. Because the factor is exact, every result shown is the full value — no rounding is required in any of them.
Example 1 — Convert 1 inch to centimeters
Formula: centimeters = inches × 2.54 Substitute: centimeters = 1 × 2.54 Multiply: centimeters = 2.54 Displayed: 2.54 cm
One inch is exactly 2.54 centimeters. This is the definition of the inch, not a conversion, and the result requires no rounding.
Example 2 — Convert 5 inches to centimeters
Formula: centimeters = inches × 2.54 Substitute: centimeters = 5 × 2.54 Multiply: centimeters = 12.7 Displayed: 12.7 cm
Five inches equals exactly 12.7 centimeters. A common use case is a smartphone display listed at 5 inches diagonal — its actual physical diagonal length is 12.7 centimeters exactly.
Example 3 — Convert 12 inches to centimeters
Formula: centimeters = inches × 2.54 Substitute: centimeters = 12 × 2.54 Multiply: centimeters = 30.48 Displayed: 30.48 cm
Twelve inches is one foot, so one foot is exactly 30.48 centimeters. This is the underlying relationship that connects the imperial foot to the metric system, and it appears constantly in construction, engineering, and furniture dimensions.
Example 4 — Convert 36 inches to centimeters
Formula: centimeters = inches × 2.54 Substitute: centimeters = 36 × 2.54 Multiply: centimeters = 91.44 Displayed: 91.44 cm
Thirty-six inches is one yard, so one yard equals exactly 91.44 centimeters. A yard of fabric, a yardstick, and any other yard-based measurement all convert to 91.44 centimetres exactly.
Example 5 — Convert 0.5 inches to centimeters
Formula: centimeters = inches × 2.54 Substitute: centimeters = 0.5 × 2.54 Multiply: centimeters = 1.27 Displayed: 1.27 cm
Half an inch equals exactly 1.27 centimeters. This value appears frequently in plumbing, where half-inch pipe and fittings are common nominal sizes, and in hobby work where small dimensions cross between the two systems.
Inches to centimeters conversion chart
The table below lists the equivalent of common inch values in centimeters. Every number is exact, generated from the same formula used by the interactive converter above.
| Inches (in) | Centimeters (cm) |
|---|---|
| 0.25 in | 0.635 cm |
| 0.5 in | 1.27 cm |
| 1 in | 2.54 cm |
| 2 in | 5.08 cm |
| 3 in | 7.62 cm |
| 5 in | 12.7 cm |
| 6 in | 15.24 cm |
| 8 in | 20.32 cm |
| 10 in | 25.4 cm |
| 12 in | 30.48 cm |
| 15 in | 38.1 cm |
| 18 in | 45.72 cm |
| 20 in | 50.8 cm |
| 24 in | 60.96 cm |
| 30 in | 76.2 cm |
| 36 in | 91.44 cm |
| 40 in | 101.6 cm |
| 48 in | 121.92 cm |
| 60 in | 152.4 cm |
| 72 in | 182.88 cm |
| 100 in | 254 cm |
How to use this converter
-
Type a value in the Inches field.
Decimals such as
12.5or0.75are accepted, as are whole numbers. You can also paste a value from elsewhere. - Watch the Centimeters field update instantly. The result refreshes on every keystroke with no delay and no loading indicator — the arithmetic runs locally in your browser.
- Adjust the display precision if you want a shorter figure. The default of six decimal places is more than enough for the exact values produced here, and even two decimals are usually sufficient for everyday use. Higher precision is available for engineering and manufacturing work.
- Copy the result with the Copy button. The numeric value is placed on your clipboard and the action is confirmed visually and to screen readers.
- Use Swap to reverse the direction. The Swap button moves the current centimeter value into the input and switches the conversion to centimeters to inches, so you can convert in the other direction without re-typing.
- Use Reset to start again. Reset clears the input, restores the empty state, and returns focus to the input field.
Practical uses for inches to centimeters conversion
TV, monitor, and phone screen diagonals
Display sizes are advertised in inches almost everywhere in the world, even in countries that otherwise use the metric system. A 55-inch television has a diagonal of exactly 139.7 centimeters; a 6.1-inch phone screen is exactly 15.494 centimeters. When shopping in a country that measures furniture or room space in centimeters, converting the screen size helps you judge whether a display will fit the space you have available.
Clothing and shoe sizes
Body measurements in the United States are usually given in inches, while European and many Asian garment size charts use centimeters. A chest measurement of 38 inches is exactly 96.52 centimeters, and a waist of 32 inches is exactly 81.28 centimeters. Shoe sizing is even more irregular across countries, but the underlying foot length is normally given in centimeters on international sizing charts, so converting your measured foot length from inches is the most reliable way to find your size abroad.
Furniture and room planning
Furniture sold internationally is often specified in one system and used in another. A sofa with a depth of 34 inches is 86.36 centimeters deep; a bed described as "queen" in the United States (60 × 80 inches) measures exactly 152.4 × 203.2 centimeters. Knowing the exact centimeter figure prevents surprises when a piece has to fit through a doorway or into a space measured in metric units.
DIY, woodworking, and hobby projects
Plans, templates, and blueprints arrive in both systems. A woodworking plan dimensioned in inches — say a 3.5-inch rail — converts to exactly 8.89 centimeters. Hobby kits imported from the United States often use fractional inches, and the exact centimeter equivalent is the safest way to transfer a measurement to a metric ruler or a metric cutting guide.
Travel, luggage, and airline rules
Airline baggage limits are quoted in both systems, and the conversions are exact. A carry-on described as "22 × 14 × 9 inches" measures exactly 55.88 × 35.56 × 22.86 centimeters. Since airlines measure baggage in the units used at the airport, having the exact figure in both systems lets you check your bag against the rules at either end of the journey.
Product specifications and technical documents
Technical datasheets frequently list dimensions in inches even when the rest of the document is metric. A circuit board with a dimension of 2.5 inches is 6.35 centimeters; a bolt with a length of 4 inches is 10.16 centimeters. Because the conversion factor is exact, the metric figure you calculate is the same one the manufacturer would print on a metric version of the same document.
Frequently asked questions
How do you convert inches to cm?
Multiply the inch value by 2.54.
For example, 12 inches multiplied by 2.54 equals exactly 30.48 centimeters. The value 2.54 is the exact number of centimeters in one international inch, fixed by the 1959 yard and pound agreement. Because it is a definition rather than a measurement, the result is exact.
How many cm is 1 inch?
One inch is exactly 2.54 centimeters.
Unlike most conversion factors, this value is exact by definition, so the result of multiplying any inch value by 2.54 is itself exact (subject only to the ordinary limits of floating-point representation in the computer performing the arithmetic). There is no rounding required and no repeating decimal to worry about.
How many cm is 12 inches?
Twelve inches equals exactly 30.48 centimeters.
Twelve inches is also one foot, so one foot is exactly 30.48 centimeters. This is the underlying relationship that connects the imperial foot to the metric system, and it appears throughout construction, engineering, and furniture measurements that cross between the two systems.
Is 2.54 exactly correct?
Yes. The international inch has been defined as exactly 2.54 centimeters since 1959.
The 1959 international yard and pound agreement, signed by the United States, the United Kingdom, Canada, Australia, New Zealand, and South Africa, fixed the international inch at exactly 2.54 centimeters. It is a legal definition, not a measurement, and therefore has no margin of error.
How do I convert cm back to inches?
Divide the centimeter value by 2.54.
For example, 30.48 centimeters divided by 2.54 equals 12 inches, returning the original value. Because multiplication and division are inverse operations, converting a value in one direction and then back always returns the original number. M-Convert provides a dedicated centimeters to inches converter for this direction.
What is 5 feet 6 inches in cm?
Five feet six inches equals 66 inches, which is exactly 167.64 centimeters.
Five feet is 60 inches, plus six inches makes 66 inches total. Multiply 66 by 2.54 to get 167.64 centimeters. The conversion is exact, so a person whose height is recorded as 5′ 6″ is exactly 167.64 centimeters tall. You can also use the feet to inches converter first if you prefer to work in inches.
Why do screen sizes use inches?
Screen diagonals have been measured in inches because the display industry developed first in the United States and the United Kingdom.
The convention has persisted long after most of the world adopted the metric system, largely because consumers worldwide recognise inch-based sizes and manufacturers want a single global label. In practice, this means that even in fully metric countries, a phone listed at 6.1 inches is the standard way the product is described, and converting that figure to centimeters is the only way to compare it against a metric ruler.
How precise is the displayed result?
The calculation itself is exact, and only the display rounds to the number of decimals you choose.
Multiplying by 2.54 does not introduce a repeating decimal for terminating-decimal inputs, so the full result is captured by the IEEE-754 double format with no loss. The display shows 6 decimal places by default with trailing zeros trimmed, and the precision can be changed from 0 to 12 decimal places. Changing the display precision never changes the underlying value.