Convert Millimeters to Inches
Convert Millimeters to Inches instantly. 1 Millimeter (mm) equals 0.03937 Inches (in).
Millimeters to Inches conversion table
| Millimeters (mm) | Inches (in) |
|---|---|
| 1 mm | 0.03937 in |
| 2 mm | 0.07874 in |
| 3 mm | 0.1181 in |
| 5 mm | 0.1969 in |
| 10 mm | 0.3937 in |
| 20 mm | 0.7874 in |
| 50 mm | 1.9685 in |
| 100 mm | 3.937 in |
| 500 mm | 19.685 in |
| 1,000 mm | 39.3701 in |
1 Millimeter = 0.03937 Inches · multiply Millimeters by 0.03937
About converting Millimeters to Inches
Millimeters (mm) and Inches (in) are both units of length, so converting between them is a single multiplication: multiply your Millimeters figure by 0.03937. Ten Millimeters comes to 0.3937 Inches, and a hundred works out at 3.937 Inches.
Rule of thumb: going from Millimeters to Inches divides, so the figure always shrinks — it takes about 25.4 Millimeters to make a single Inch. If your answer came out bigger, you have the conversion the wrong way round.
What is a Millimeter?
A millimeter is one thousandth of a meter, and it is where metric measurement starts getting genuinely precise. It is the working unit of engineering drawings, machine shops, rainfall figures and camera lenses — a "50 mm lens" and "12 mm of rain overnight" are both millimeter measurements. Technical drawings in most of the world default to millimeters precisely because it lets a draughtsman specify a whole component without ever writing a decimal point.
What is an Inch?
An inch is exactly 2.54 centimeters — a rare case where an imperial and a metric unit line up on a tidy number, because the inch was redefined in terms of the meter rather than the other way round. It has quietly outlived most imperial units by attaching itself to technology: screen sizes, wheel and tyre diameters, plumbing pipe, and screw threads are specified in inches worldwide, so even in thoroughly metric countries people buy a 15-inch laptop and 17-inch wheels.
To put both in perspective: a credit card is about 0.76 millimeters thick, while an inch is about the width of an adult thumb.
The converter above updates as you type, and the table lists common values for quick reference. Need the opposite direction? Use the Inches to Millimeters converter, or browse all Length converters.
Frequently asked questions
How many Inches are in one Millimeter?
There are 0.03937 Inches in one Millimeter.
How do I convert Millimeters to Inches?
Multiply the number of Millimeters by 0.03937. For example, 10 Millimeters = 0.3937 Inches.
What is 100 Millimeters in Inches?
100 Millimeters is equal to 3.937 Inches.
How do I convert Inches to Millimeters?
Multiply the Inches value by 25.4 (or divide by 0.03937).
Is this Millimeters to Inches conversion exact?
The definition is exact — Millimeters and Inches are both fixed against the same base by international agreement — but the decimal shown here is rounded for readability, because the true ratio does not terminate. For engineering or scientific work, carry more decimal places than this page displays.
What is a Millimeter?
A millimeter is one thousandth of a meter, and it is where metric measurement starts getting genuinely precise. It is the working unit of engineering drawings, machine shops, rainfall figures and camera lenses — a "50 mm lens" and "12 mm of rain overnight" are both millimeter measurements. Technical drawings in most of the world default to millimeters precisely because it lets a draughtsman specify a whole component without ever writing a decimal point.
What is an Inch?
An inch is exactly 2.54 centimeters — a rare case where an imperial and a metric unit line up on a tidy number, because the inch was redefined in terms of the meter rather than the other way round. It has quietly outlived most imperial units by attaching itself to technology: screen sizes, wheel and tyre diameters, plumbing pipe, and screw threads are specified in inches worldwide, so even in thoroughly metric countries people buy a 15-inch laptop and 17-inch wheels.