Mass is a base dimension in the International System of Units. The SI unit of mass is the kilogram, which is equal to the mass of the international prototype of the kilogram (3rd CGPM, 1901).

Maple knows the units of mass listed in the following table.

An asterisk ( * ) indicates the default context, an at sign (@) indicates an abbreviation, and under the prefixes column, SI indicates that the unit takes all SI prefixes, IEC indicates that the unit takes IEC prefixes, and SI+ and SI- indicate that the unit takes only positive and negative SI prefixes, respectively.  Refer to a unit in the Units package by indexing the name or symbol with the context, for example, gram[SI] or lb[avoirdupois]; by using an abbreviation, for example, AT; or, if the context is indicated as the default, by using only the unit name or symbol, for example, gram or lb.

The units of mass are defined as follows.

A tonne is defined as $1000$ kilograms.

An electron mass is defined as $9.1093897\times {10}^{\mathrm{-28}}$ gram.

An atomic mass unit is defined as $\frac{1}{12}$ the mass of the carbon-12 atom, or approximately $1.6605402\times {10}^{\mathrm{-27}}$ kilogram.

An avoirdupois, troy, or apothecary grain is defined as $0.00006479891000$ kilogram or as $\frac{1}{7000}$ avoirdupois pound.

A metric grain is defined as $50$ milligrams.

An avoirdupois drachm is defined as $\frac{1}{16}$ avoirdupois ounce.

An avoirdupois ounce is defined as $\frac{1}{16}$ avoirdupois pound.

An avoirdupois pound is defined as $0.45359237$ kilogram.

An avoirdupois clove is defined as $8$ avoirdupois pounds.

An avoirdupois stone is defined as $14$ avoirdupois pounds.

An avoirdupois quarter is defined as $28$ avoirdupois pounds.

An avoirdupois cental is defined as $100$ avoirdupois pounds.

An avoirdupois quintal is defined as $100$ avoirdupois pounds.

A metric quintal is defined as $100$ kilograms.

A short hundredweight is defined as $100$ avoirdupois pounds.

A long hundredweight is defined as $112$ avoirdupois pounds.

A metric hundredweight is defined as $50$ kilograms.

An avoidupois wey is defined as $252$ avoirdupois pounds.

A kip (kilo Imperial pound) is defined as $1000$ avoirdupois pounds.

A short ton is defined as $2000$ avoirdupois pounds.

A long ton is defined as $2240$ avoirdupois pounds.

A metric ton is defined as $1000$ kilograms.

A troy pennyweight is defined as $24$ troy grains.

A troy ounce is defined as $20$ troy pennyweights.

A troy pound is defined as $12$ troy ounces.

An apothecary scruple is defined as $20$ apothecary grains.

An apothecary drachm is defined as $3$ apothecary scruples.

An apothecary ounce is defined as $8$ apothecary drachms.

An apothecary pound is defined as $12$ apothecary ounces.

A (short) assay ton is defined as that mass such that milligrams per (short) assay ton equals troy ounces per short ton, or $\frac{7}{240}$ kilogram.

A long assay ton is defined as that mass such that milligrams per long assay ton equals troy ounces per long ton, or $\frac{49}{1500}$ kilogram.

A metric carat is defined as $0.2$ gram.

A diamond carat is defined as $3.2$ troy grains.

A millier is defined as a tonne.

A mite is defined as a $\frac{1}{20}$ avoirdupois grain.

A mancus is defined as a $2$ avoirdupois ounces.

A merchant pound is defined as a $16$ avoirdupois ounces.

A mast is defined as a $2.5$ troy pounds.

A slug is defined as the mass that is accelerated at $1$ foot per second squared by a force of $1$ poundforce, or $14.59390294$ kilograms.

A metric slug or hyl is defined as that mass that is accelerated at $1$ meter per second squared by a force of $1$ kilogramforce, or $9.80665$ kilograms.

A slinch or blob is defined as that mass that is accelerated at $1$ inch per second squared by a force of $1$ poundforce, or $\frac{8896443230521}{50800000000}$ kilograms.

A crith is defined as the mass of $1$ liter of hydrogen at standard temperature and pressure, approximately $89.885$ milligrams.

A jupiter is defined as the mass of the planet Jupiter, approximately equal to $1.899$ yottatonnes.

A planck mass is defined as the square root of: the planck constant times the speed of light, divided by twice $\mathrm{\pi }$ times the Newtonian gravitational constant.

$\mathrm{convert}\left('\mathrm{kilogram}'\,'\mathrm{dimensions}'\,'\mathrm{base}'=\mathrm{true}\right)$

$\mathrm{mass}$

$\mathrm{convert}\left(1\,'\mathrm{units}'\,'\mathrm{ton}\left[\mathrm{long}\right]'\,'\mathrm{stone}'\right)$

$160$