Meters to Decimeters (m to dm)

1 meter equals 10 decimeters exactly.

1 meter = 10 decimeters

How to convert meters to decimeters

To convert meters to decimeters, multiply the number of meters by 10. This factor is exact. To go the other way, multiply decimeters by 0.1.

decimeters = meters × 10

Example: 10 meters = 100 decimeters.

About these units

Meter (m)

Metric (SI)Current unit

The SI base unit of length. Since 1983 it is defined as the distance light travels in a vacuum in 1/299,792,458 of a second.

Meter comes from the Greek metron, a measure. In 1791 the French National Assembly defined it as one ten-millionth of the distance from the equator to the North Pole along a great circle through Paris, after rejecting the length of a seconds pendulum because that length changes with local gravity. The surveyors Delambre and Méchain measured the meridian arc, and in 1799 a platinum bar known as the Mètre des Archives became the physical standard. NIST notes that this Earth-based meter turned out to be about 0.2 mm shorter than the true pole-to-equator fraction it was meant to represent.

The 1875 Treaty of the Meter created the CGPM and the BIPM to look after common standards, and in 1889 a platinum-iridium prototype bar took over; the original is still kept at the BIPM. In 1960 the meter was tied to 1,650,763.73 wavelengths of an orange-red krypton-86 line, and in 1983 to the speed of light, which made length a quantity derived from the time standard. The 2018 revision reworded that definition without changing the meter's size. NIST offers a handy yardstick for scale: a pace, meaning two steps, is roughly a meter or a yard.

The meter is the reference unit for length on this site.

Sources: BIPM: history of the metre; NIST: the meter and the SI redefinition; Wikipedia: Metre

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

Related conversions

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