Loaded dice are dice altered to favor certain faces, usually by hiding weight inside, shaving faces so the die settles a particular way, or drilling and refilling the pips. A fair die shows each face 16.67% of the time. A loaded one doesn’t, and a salt water float test plus a long run of recorded rolls will usually expose it.
Mass or shape
Mass loading puts something heavy off-center. A cavity gets drilled, a slug of dense metal goes in, and the hole is plugged and refinished. Historically lead or mercury, tungsten now. The heavy side sinks, so the opposite face comes up more often: weight a die toward the 1 and it shows 6 more than it should.
Shape loading changes the geometry instead. Faces cut or sanded so the cube isn’t quite a cube, and the die settles on the larger pair more often. Gambling literature names the variants: flats have one dimension shortened, bevels have slightly convex faces. A fraction of a millimeter is enough, and it’s invisible to the eye.
Pip loading sits between the two. Pips drilled into the surface and filled with paint lighter than the plastic removed. The 6 face loses the most material, so the die tilts toward landing 6 up. Casino dice fill their pips with density-matched material, flush with the surface, for exactly this reason.
Not every biased die is a cheating die. The difference between a sloppy die and a loaded die is intent.
Roman dice get misreported here constantly. They were wildly asymmetrical, with 80 to 90 percent of surviving examples having a side that differs from the others by 5 percent or more. A 2022 study by Jelmer Eerkens and Alex de Voogt in Archaeological and Anthropological Sciences argues this wasn’t cheating: given blank asymmetrical dice to mark up, modern students independently put the 1 and the 6 on the larger faces, matching the Roman pattern.
How to test a die
The salt water float test. Dissolve enough salt in warm water that the die floats, roughly six tablespoons in a third of a cup. Spin it, note the top face, then push it fully under so surface tension doesn’t hold it. Twenty spins minimum. A weighted die keeps showing the same face.
The spin test. Spin the die on a hard flat surface like a top, pinched between two fingers on opposite corners. A fair die spins smoothly and stops at random. A weighted one wobbles and tends to stop the same way.
The dimension check. Calipers on each axis. Every axis should measure the same. This catches flats, which the float test won’t.
The frequency test, which is boring and works. Roll it a lot and write down the results. A hundred rolls tells you almost nothing, a thousand starts to be informative. Each face should land near 16.67%, and one running consistently above that over a long run is a real signal.
Where it stops being a party trick
Owning loaded dice is legal in most places. Novelty shops sell them and stage magicians use them. Using them for money in a licensed casino is a serious crime. Nevada’s NRS 465.083 reads: “It is unlawful for any person, whether the person is an owner or employee of or a player in an establishment, to cheat at any gambling game.” NRS 465.015 defines cheating as altering the result of a game, the amount or frequency of payment, or the value of a wagering instrument. A first offense is a category C felony: one to five years in prison, restitution, and a fine up to $10,000. NRS 465.085 separately bars manufacturing or selling dice intended for use in violating the chapter.
None of that applies to your kitchen table. If you just want rolls you can trust, buy casino-grade dice or use the dice roller here, which runs on your browser’s random number generator. The dice probability chart gives you a baseline to compare against, and dice faces covers how casino dice are built.
FAQ
How do you tell if dice are loaded?
Float the die in heavily salted water and spin it twenty times. A weighted die keeps turning the same face upward, while a fair one settles randomly. Back that up with calipers on each axis and a long run of recorded rolls compared against 16.67% per face.
Are loaded dice illegal?
Owning them generally isn’t. Using them to cheat in licensed gambling is. Nevada’s NRS 465.083 makes cheating at any gambling game a category C felony on a first offense, punishable by one to five years in prison and up to $10,000 in fines.
Does the salt water test actually work?
Partly. It detects uneven mass, which covers weighted inserts and drilled cavities, but it cannot detect shaved dice, which are biased by geometry rather than weight. Surface tension produces false results if you don’t push the die under between spins. Treat it as a screening tool.
Are cheap dice biased?
Slightly, though not on purpose. Pips drilled into the surface and filled with paint remove more material from the 6 face than the 1, nudging the distribution. Casino dice avoid this with flush, density-matched pip fill.