Imperial to Metric Unit Converter

Imperial and metric units appear together in travel, engineering, cooking, education, health, shipping, and international trade. The metric system organizes related units around powers of ten, while Imperial measurements use historical ratios such as 12 inches per foot and 14 pounds per stone. This converter bridges the systems with established factors and restricts each conversion to compatible dimensions. Length conversions are defined exactly in modern standards. One inch equals exactly 25.4 millimeters, which also means one foot equals 0.3048 meter, one yard equals 0.9144 meter, and one mile equals 1.609344 kilometers. Because these definitions are exact, any rounding comes only from how many decimal places are displayed, not from uncertainty in the factor. Ten inches, for example, is exactly 25.4 centimeters. Mass conversions use the international avoirdupois pound. One pound equals exactly 0.45359237 kilogram, one ounce equals one sixteenth of that amount, and one stone equals 14 pounds. These factors suit body weight, packaged goods, freight, recipes, and most modern references using Imperial pounds and ounces. They should not be confused with troy ounces, which are a different mass unit used mainly for precious metals. Volume needs careful labeling. This page uses Imperial volume: one Imperial gallon equals exactly 4.54609 liters. An Imperial pint is one eighth of a gallon, and an Imperial fluid ounce is one 160th of a gallon. US customary gallons, pints, cups, and fluid ounces are smaller and require different factors. Check the country and label on the source measurement before converting a recipe, fuel quantity, or container capacity. Temperature does not use a simple multiplication because Fahrenheit and Celsius have different zero points. Celsius equals Fahrenheit minus 32, multiplied by five ninths. Kelvin uses the same interval as Celsius and adds 273.15 to the Celsius result. Thus, 68 degrees Fahrenheit becomes 20 degrees Celsius or 293.15 kelvin. Negative Fahrenheit values are accepted because they are valid temperatures. Choose the measurement category first, enter the value, and then select the Imperial source and metric destination units. Results retain useful decimal precision for technical work while remaining readable. Unit conversion does not account for measurement tolerance, instrument calibration, or significant-figure rules, so round the result appropriately for your application. For safety-critical engineering, medicine, or regulated trade, verify the source unit and required standard before relying on any converted quantity.