= Gross mass
{title2=$m_{\mathrm g}$}
= Gross weight
{synonym}
<Gross mass> is the <mass> of the complete specified load, including its contents and the packaging counted as <tare mass>. For that same boundary,
$$
m_{\mathrm g}=m_{\mathrm n}+m_{\mathrm t}.
$$
The gross indication in OIML's weighing terminology is obtained with neither a <tare device> nor a <preset tare device> operating, after an initial zero indication.<Non-automatic weighing instruments, Part 1>[T.5.2, note and T.5.2.1, printed p16]{ref} A full crate's <gross mass> consequently differs from an individual jar's <gross mass>, because the specified loads differ.
Consider four jars, each containing $0.50\,\mathrm{kg}$ of material and having an empty-container <tare mass> of $0.20\,\mathrm{kg}$. An outer crate adds $0.80\,\mathrm{kg}$. For the complete load, the <net mass> of the contents, <composite tare mass>, and <gross mass> are respectively
$$
\begin{aligned}
m_{\mathrm n}&=4(0.50)=2.00\,\mathrm{kg},\\
m_{\mathrm t}&=4(0.20)+0.80=1.60\,\mathrm{kg},\\
m_{\mathrm g}&=4(0.50+0.20)+0.80=\boxed{3.60\,\mathrm{kg}}.
\end{aligned}
$$
These are chosen bookkeeping values, assuming the listed components exhaust the load and each component is counted once.
\Image[/gross-tare-net-load-boundary.png]
{title=Gross, composite tare and net mass of four jars in one outer crate}
{description=Original chosen example: 2.00 kg of contents, 0.80 kg of empty jars and 0.80 kg of outer crate. The colored parts represent disjoint portions of the complete load.}
Subtracting the full <composite tare mass> from the complete <gross mass> gives $3.60-1.60=2.00\,\mathrm{kg}$ of contents. If the jars' $0.80\,\mathrm{kg}$ has already been removed from an intermediate total, subtracting the same full <composite tare mass> again gives $1.20\,\mathrm{kg}$. The missing $0.80\,\mathrm{kg}$ is precisely the duplicated deduction. \b[Use one load boundary and subtract each packaging component once.]
The <gross mass> also remains relevant to <maximum weighing capacity> when a <subtractive tare device> reduces the available net-load range.<Non-automatic weighing instruments, Part 1>[T.2.7.4, subtractive tare device, printed p11]{ref} For an illustrative instrument modeled with a $1.000\,\mathrm{kg}$ gross-load limit, a $0.120\,\mathrm{kg}$ container leaves $0.880\,\mathrm{kg}$ for contents. At that limit the complete load still has <gross mass> $1.000\,\mathrm{kg}$, even though the tared display reports only its contents.
For a stationary ideal <weighing scale>, the <normal contact force> associated with a complete load is related to its <gravitational weight>. A displayed <net mass> is a processed indication of that load; it is not the full supported <mass>. Changes in the <gravitational field>, <measurement calibration>, or the load boundary must therefore be distinguished when interpreting a reading.
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