Gold Density Test Calculator
A density test is a simple, non-destructive way to check whether an item is likely solid gold or a lower-density fake. It works on Archimedes' principle: weigh the item dry, then measure the volume of water it displaces when submerged, since one milliliter of water equals one cubic centimeter. This gold density test calculator divides the mass in grams by the displaced volume in milliliters to give the density in grams per cubic centimeter, then compares it to known gold densities. Pure 24 karat gold has a density of about 19.3 grams per cubic centimeter, while gold alloys are lower: 18 karat is roughly 15.5 and 14 karat about 13. A result well below the expected density for the marked karat suggests the item is plated, hollow, or alloyed differently than stamped. Every figure here is computed deterministically from your two measurements, so the same mass and volume always return the same density. Enter your measurements below to test a suspect piece, compare a result to the density for its hallmark, or screen scrap before buying, with a worked example that reconciles exactly to the calculator defaults so you can follow each step. A density test is a screening tool, not proof; assay testing gives a definitive answer.
Density equals mass divided by displaced volume, with one milliliter equal to one cubic centimeter. A 38.6 g item displacing 2 mL of water has a density of 19.30 g per cu cm, matching pure gold.
Gold density test formula
density = mass / displaced volume
1 mL of water = 1 cubic centimeter
mass in grams, displaced volume in milliliters, density in g per cu cm
Submerging the item displaces a volume of water equal to the item's volume, since 1 milliliter equals 1 cubic centimeter. Dividing the dry mass by that volume gives the density, which is then compared to known gold values.
Worked example
Take an item with a dry mass of 38.6 grams that displaces 2 milliliters of water when submerged.
- Volume equals displaced water: 2 mL = 2 cubic centimeters
- Density: 38.6 / 2 = 19.30 g per cubic centimeter
- 19.30 is the density of pure 24 karat gold
The density is 19.30 grams per cubic centimeter, matching pure gold, which reconciles with the calculator's default inputs exactly. A density test screens, it does not prove purity.
Gold Density Test Calculator: frequently asked questions
How do I measure displaced volume?
Fill a graduated container with water, note the level, submerge the item fully without touching the sides, and note the new level. The difference is the displaced volume in milliliters. A more accurate method weighs the item in air and again suspended in water.
What density should solid gold show?
Pure 24 karat gold is about 19.3 grams per cubic centimeter. Alloys are lower: 18 karat around 15.5, 14 karat around 13, and 10 karat around 11.6, depending on the other metals. Compare your result to the value expected for the stamped karat.
Can a density test detect a fake?
It can flag many fakes, because gold is unusually dense and most substitute metals are lighter. A result well below the expected density suggests plating, hollow construction, or a different alloy. However, dense fillers like tungsten can mimic gold's density, so density alone is not conclusive.
Does the test damage the item?
No. A density test is non-destructive: it only requires weighing and submerging the item in water. This makes it useful for screening pieces you do not want to scratch or cut, unlike acid testing, which marks the item.
Is a density test definitive?
No. It is a screening tool. A passing density is reassuring but not proof, since some dense metals can mimic gold, and surface plating over a similar-density core can fool it. For certainty, use professional assay or X-ray fluorescence testing.
Official sources
- Coin metal content and precious-metal specifications: US Mint. As at 25 June 2026.
Reviewed by the CalculatorHub team, edited by James Graham, 25 June 2026. See our methodology. This is general information, not financial, tax, legal or investment advice.