How much does an 18k gold ring weigh?
An 18K yellow gold ring weighs about 1.56 grams for every 100 cubic millimetres of metal in it, so the total depends on the ring's volume. Weight is volume times the alloy's density, and 18K yellow gold is 15.58 grams per cubic centimetre. The other 18K colours differ: white gold with nickel is lighter, at 14.64, and white gold with palladium is heavier, at 15.84.
3D Jewelry Designer2 min read
How do you work out what an 18K gold ring weighs?
Multiply the volume of metal in the ring by the density of the alloy. CAD software usually reports volume in cubic millimetres, and a cubic centimetre holds 1,000 of them, so:
grams = volume (mm³) ÷ 1000 × density (g/cm³)For 100 mm³ of 18K yellow gold that is 100 ÷ 1000 × 15.58, or 1.558 grams.
- Measure the metal volume. The free metal weight calculator reads a .3dm, .glb, .stl or .obj file and measures it, net of the stones. The file never leaves your browser.
- Name the alloy, not just the karat. Each 18K alloy has its own density, listed below.
- Multiply. The calculator does this for every common alloy at once; how to calculate gold weight from a 3D model walks through it by hand.
Does the colour of 18K gold change the weight?
Yes. The karat fixes the gold: 18K is 18 parts in 24, or 750 parts per thousand. The other six parts, more copper for rose gold and nickel or palladium for white, change the density. This is what 100 mm³ of metal weighs in each 18K alloy, with sources under the full table below:
| 18K alloy | Density (g/cm³) | Grams per 100 mm³ |
|---|---|---|
| Yellow gold | 15.58 | 1.558 |
| White gold (nickel) | 14.64 | 1.464 |
| White gold (palladium) | 15.84 | 1.584 |
| Rose or red gold | 15.18 | 1.518 |
| Green gold | 15.90 | 1.590 |
White gold is the one to check: ask your caster whether they pour nickel or palladium white before you quote.
How does 18K gold compare with other metals?
Gold is denser than the metals it is alloyed with, so the same ring weighs more at a higher karat. The full table, also on the alloy density table page, puts 18K beside 9K to 24K gold, platinum, palladium and silver, with the supplier source for each density.
| Alloy | Density g/cm³ | Karat | Grams per 1000 mm³ |
|---|---|---|---|
| 9K Yellow Gold (approx.)1 | 11.50 | 9K | 11.50 |
| 10K Rose Gold2 | 11.59 | 10K | 11.59 |
| 10K White Gold (nickel)2 | 11.07 | 10K | 11.07 |
| 10K Yellow Gold2 | 11.57 | 10K | 11.57 |
| 14K Rose Gold2 | 13.26 | 14K | 13.26 |
| 14K White Gold (nickel)2 | 12.61 | 14K | 12.61 |
| 14K White Gold (palladium)3 | 14.11 | 14K | 14.11 |
| 14K Yellow Gold2 | 13.07 | 14K | 13.07 |
| 18K Green Gold2 | 15.90 | 18K | 15.90 |
| 18K Red Gold2 | 15.18 | 18K | 15.18 |
| 18K Rose Gold2 | 15.18 | 18K | 15.18 |
| 18K White Gold (nickel)2 | 14.64 | 18K | 14.64 |
| 18K White Gold (palladium)3 | 15.84 | 18K | 15.84 |
| 18K Yellow Gold2 | 15.58 | 18K | 15.58 |
| 22K Yellow Gold4 | 17.73 | 22K | 17.73 |
| 24K Yellow Gold5 | 19.32 | 24K | 19.32 |
| Palladium 9506 | 12.10 | 950 | 12.10 |
| Platinum 900 (iridium)2 | 21.54 | 900 | 21.54 |
| Platinum 950 (cobalt)5 | 20.10 | 950 | 20.10 |
| Platinum 950 (iridium)5 | 21.50 | 950 | 21.50 |
| Platinum 950 (ruthenium)5 | 20.70 | 950 | 20.70 |
| Sterling Silver 9255 | 10.36 | 925 | 10.36 |
Densities are supplier figures, not estimates. One label can cover more than one alloy, so a shop confirms or edits its own in the studio under Setup, Metals.
What does a weight from the model leave out?
It is the weight of the metal as drawn. Three things sit outside it:
- A different finger size. The same design holds more metal at a larger size, so measure the model at the ring size you are making.
- The stones. The calculator keeps stones that are separate objects out of the metal, and its gross figure adds them back at 0.2 grams per carat.
- Casting loss. A caster melts more metal than the ring keeps, for the sprue and for what filing and polishing take off, and sets their own allowance for it.
Questions
Is 18K gold heavier than 14K gold?
Yes, for the same ring. 18K yellow gold is 15.58 grams per cubic centimetre and 14K yellow gold is 13.07, so 100 cubic millimetres of metal weighs 1.558 grams in 18K and 1.307 grams in 14K.
How do I weigh a ring I already have?
Put it on a jeweller's scale. That gives the gross weight, stones included, so take off 0.2 grams for every carat of stones to leave the metal.
Related
- Gold Weight Calculator from a 3D Model
Drop an STL or 3DM file and get the gram weight in 9k to 24k gold, silver and platinum, gross and net of stones. Free.
- Gold karat: what 10K, 14K, 18K and 24K mean
Karat measures gold purity in 24ths. The fineness of 9K to 24K gold, and how karat changes a ring's colour, weight and gold price.
- How to calculate gold weight from a 3D model
Work out the metal weight of a ring from its CAD volume and the alloy density, with the published density figures for 14K, 18K, white gold and platinum.