What is long ton (UK)?

A long ton is a unit of mass historically used in the United Kingdom, equal to 2,240 pounds. It is used in shipping, naval architecture, and some industrial contexts in the UK.

Real-world uses

The long ton was historically used in British shipping, coal mining, and iron/steel trade. Naval vessel displacement is sometimes still quoted in long tons. It occasionally appears in older British engineering specifications and historical trade records.

History

The long ton of 2,240 pounds derives from the traditional English system of 20 hundredweight (each 112 lb). It was the standard British ton until metrication in the 1970s largely replaced it with the metric tonne in commerce.

Common mistakes

Confusing the long ton (2,240 lb / 1,016 kg) with the short ton (2,000 lb / 907 kg) or the metric tonne (2,205 lb / 1,000 kg). This 12% difference can cause major commercial discrepancies.

What is milligram?

A milligram is a metric unit of mass equal to one thousandth of a gram. It is commonly used in pharmaceutical dosing, nutritional content labelling, and laboratory chemistry.

Real-world uses

Milligrams are the standard unit for pharmaceutical dosages (e.g., 500 mg ibuprofen), nutritional supplement quantities, and blood test results such as cholesterol levels (mg/dL). Environmental scientists measure pollutant concentrations in mg/L.

History

The milligram was established with the metric system's prefix conventions in the 1790s. Its importance grew dramatically with modern pharmacology, where precise small-mass measurements became critical for drug safety and efficacy.

Common mistakes

Confusing milligrams with micrograms—a factor-of-1000 error that can be dangerous in medication dosing. The abbreviation "mcg" is sometimes used for micrograms to avoid confusion with "mg."

When is this conversion used?

Converting between long ton (UK) and milligram is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region.

Worked examples

1 long ton (UK) = 1.016047e+09 milligram

1 milligram = 0.000001 kilogram

How to convert long ton (UK) to milligram

To convert long ton (UK) to milligram, multiply the value by 1.016047e+09.

To convert milligram back to long ton (UK), multiply by 9.842065e-10.

Measurement standards

The kilogram is defined by fixing the Planck constant to exactly 6.62607015 × 10⁻³⁴ joule-seconds, as established at the 26th General Conference on Weights and Measures in 2018. This ended the last SI definition based on a physical artefact.

Did you know?

The International Prototype of the Kilogram, a platinum-iridium cylinder stored near Paris since 1889, was found to have drifted by about 50 micrograms relative to its copies over a century — roughly the mass of a fingerprint.

Quick reference: long ton (UK) to milligram

Common values

Available Mass units

• kilogram conversions
• gram conversions
• pound conversions
• ounce conversions
• tonne conversions
• milligram conversions
• microgram conversions
• stone conversions
• short ton (US) conversions
• long ton (UK) conversions

More long ton (UK) conversions

• Convert long ton (UK) to kilogram
• Convert long ton (UK) to gram
• Convert long ton (UK) to pound
• Convert long ton (UK) to ounce
• Convert long ton (UK) to tonne
• Convert long ton (UK) to milligram
• Convert long ton (UK) to microgram
• Convert long ton (UK) to stone
• Convert long ton (UK) to short ton (US)