Weight

In NetHack, weight is a measure of an item's heaviness. Carrying too much weight will increase your encumbrance, rendering you burdened, stressed or possibly worse depending on the size of your load - fighting while significantly encumbered is not advised, as excessive weight lowers you speed.

NetHack expresses item weight in aum, short for "arbitrary unit of measurement". Normally, the only case where the game explicitly tells you an item's weight is when you purchase a glob of pudding from a shop. In wizard mode, however, your inventory displays the weight of each carried item. Several variants allow the player to show the weights of objects in their inventory during regular (non-wizard mode) play.

List of item weights

The following table below lists the weights of a few common items and a couple of monsters from lightest to heaviest, with all weights given in aum. Monsters have no specific weight while alive (they are instead classified by size), but their corpses do.

Item	Weight (aum)
100 gold pieces	1
gem	1
ring	3
scroll	5
wand	7
luckstone	10
tripe ration	10
lizard corpse	10
bugle	10
mirror	13
flail	15
empty bag	15
amulet	20
potion	20
food ration	20
lichen corpse	20
unicorn horn	20
mace	30
dragon scale mail	40
long sword	40
spellbook	50
fauchard	60
pick-axe	100
plate mail	450
iron ball	480
loadstone	500
human corpse	1450
dragon corpse	4500
boulder	6000

Special rules

If you are polymorphed into a giant, boulders in your inventory have no weight.

A bag of holding modifies the weight of its contents - an uncursed bag of holding effectively reduces the weight of its contents by ¹⁄₂, and a blessed one does so by ³⁄₄, while a cursed one doubles the weight. The weight of the bag itself is always 15 aum.

Origin and real-world comparisons

The weights of many items in NetHack (notably weapons and armor) are directly pulled from Dungeons and Dragons, specifically Advanced Dungeons and Dragons, which was current when Hack was written. In that game, a single unit of weight is defined as ¹⁄₁₀ of a pound (roughly 45 grams), meaning a long sword weighs 4 pounds, a human corpse weighs 145 pounds, etc. The writers of D&D notably overestimated the weights of many medieval weapons: a NetHack or D&D-style one-handed "long sword" would generally weigh closer to 2.5 pounds. Correcting this error would suggest an aum to be closer to an ounce, or ¹⁄₁₆ of a pound (roughly 30 grams).

Overall, no estimate for the weight of an aum will work for every item. For example, both weight estimates above are unrealistically low for gold coins: ¹⁄₁₀₀ of an aum equates to either .3 or .45 grams. While coins that small have been produced, they are extremely uncommon, as their small size makes them very difficult to use; even the 1.7 gram US gold dollar was considered inconvenient due to its small size. The reason for this disparity is that the developers of NetHack chose to make NetHack's gold coins weigh ¹⁄₁₀ of what they did in AD&D, so as not to make gold inconveniently heavy. Similar balance decisions (rather than realism) influence the weights of many items, while many later-added items may have simply been given fairly arbitrary weights.

Strategy

In a few cases, weight testing can be a way to identify objects, especially after price identification.