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Sources and Accuracy
Length conversions use the metre as the reference unit. Common imperial relationships are exact where standardized, such as 1 inch = 0.0254 metre and 1 foot = 0.3048 metre.
Displayed results are rounded for readability. The calculator keeps enough precision for everyday use and switches to scientific notation for very large or very small values. Last reviewed: 2026-05-21.
About These Units
mile [mi]
Definition
The mile is an imperial and US customary length unit equal to exactly 1.609344 kilometers.
History
The statute mile developed from older land-measure systems and is now standardized as 5280 feet.
Current use
Miles are used for road distances, vehicle mileage, running, aviation references, and travel in the United States and UK.
picometer [pm]
Definition
The picometer (pm) is a length unit used to express measurements in this converter.
History
This unit is included because it appears in practical measurement systems, technical references, product specifications, or everyday conversion needs.
Current use
Use picometer when comparing length values, checking specifications, converting between systems, or preparing quick estimates.