Decimeters to Inches (dm to in)

1 decimeter equals 3.937007874 inches (rounded).

1 decimeter = 3.937007874 inches

How to convert decimeters to inches

To convert decimeters to inches, multiply the number of decimeters by 3.937007874. The factor is rounded to 10 significant digits. To go the other way, multiply inches by 0.254.

inches = decimeters × 3.937007874

Example: 10 decimeters = 39.37007874 inches.

About these units

Decimeter (dm)

Metric (SI)Current unit

One tenth of a meter (10 cm). Rarely used in everyday practice.

Deci, meaning a tenth, was among the prefixes of the first metric system, and Wikipedia's prefix table dates it to 1795. The decimeter (dm) is therefore 10 centimeters, 100 millimeters or about 3.937 inches. Of all the early metric multiples it is the one that shows up least in daily speech, since people reach for centimeters or meters instead.

Its real importance is as the edge of the liter. A liter is defined as one cubic decimeter, so a 10 cm cube holds exactly one liter. Between 1901 and 1964 the liter was defined through the kilogram instead, which made it very slightly different from the cubic decimeter. The unit also survives in a few specialist places. Chemists record the path length used for specific rotation in decimeters, and ship draught marks are given in decimeters in most of the world. A standard compact disc, at 120 mm, is 1.2 dm across.

1 decimeter = 0.1 meters (exactly).

Sources: Wikipedia: Decimetre; Wikipedia: Metric prefix; NIST: metric (SI) prefixes

Inch (in)

US & ImperialCurrent unit

1/12 of a foot. Defined as exactly 25.4 millimeters since 1959, when the US and Commonwealth countries agreed a common international inch.

Latin uncia, meaning one-twelfth, is the root of both inch and ounce, and it passed into Old English as ynce. Roman measurers divided their foot into twelve unciae, and the English inch kept that twelfth. After 1066 an inch was reckoned as three barleycorns, and a 1324 statute attributed to Edward II spelled out the definition as three grains of barley, dry and round, placed end to end lengthwise. For centuries the inch was simply a twelfth of a foot, or a thirty-sixth of a yard, and the US and UK each kept their own copy of the standard yard.

Those copies differed slightly until the 1959 international agreement fixed the yard at exactly 0.9144 meter, which made the inch exactly 25.4 millimeters. The US adopted it in 1959 and the UK ratified it in 1963, effective 1964. Today the inch is still the customary unit in the United States and Canada, and the UK keeps it on road signs. Worldwide it also names display diagonals, wheel rims, tire codes and pipe sizes.

1 inch = 0.0254 meters (exactly).

Sources: Wikipedia: Inch; Wikipedia: Yard; NIST Guide to the SI, Appendix B.8: conversion factors

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