Free tools

Gold calculators for jewelers and workshops

Tools for the shop and tools for the workshop, for what you work out every day. Enter the numbers and the result appears at once.

Results are an aid to calculation and depend on the numbers you enter.

For the shop

Jeweler’s tools

For everyday buying and selling: a piece’s value, converting weight between karats, and the price per gram from the ounce price.

Piece value

From the piece’s weight and karat, and the price per gram of one karat you know.

Piece karat
Price karat

In any currency you deal in; the result is in the same currency.

85.71
857.14
50.00
907.14

Piece price per gram = price per gram × piece karat fineness ÷ price karat fineness

Karat conversion

What a weight in one karat equals in another, with the same fine gold.

From karat
To karat
8.57 g
7.50 g

Equivalent weight = weight × first karat fineness ÷ second karat fineness

Ounce and gram

The price per gram from the ounce price, or the ounce price from the price per gram. Type in either field.

Karat of the gram price

An ounce is 31.1035 grams of fine gold. In any currency you deal in; the result is in the same currency.

96.45
84.40
3,000.00

24K price per gram = ounce price ÷ 31.1035; any karat’s price per gram = 24K price per gram × the karat’s fineness ÷ 24K fineness

For manufacturing

Workshop tools

For manufacturing: karat adjustment and the alloy mix.

Karat adjustment

How much fine gold to add to raise a karat, or how much alloy to add to lower it.

Current karat
Target karat
1.67 g
11.67 g

To raise: weight × (target − current fineness) ÷ (24K fineness − target). To lower: weight × (current − target) ÷ target.

Alloy mix

How much fine gold, silver and copper go into an alloy of the karat and weight you choose.

Target karat

The rest of the alloy metal is copper. More silver gives a pale yellow, more copper a red tone.

7.50 g
1.25 g
1.25 g
2.50 g

24K gold = alloy weight × target fineness ÷ 24K fineness; the rest is alloy metal, split between silver and copper.

Karat fineness

Fineness in parts per thousand: the values the calculators above use.

  • 24K

    Fineness (per 1000)
    999.9
    Fine gold
    99.99%

  • 22K

    Fineness (per 1000)
    916.6
    Fine gold
    91.66%

  • 21K

    Fineness (per 1000)
    875
    Fine gold
    87.50%

  • 18K

    Fineness (per 1000)
    750
    Fine gold
    75.00%

  • 14K

    Fineness (per 1000)
    583.3
    Fine gold
    58.33%

GoldTag does these calculations on every invoice.

Each karat’s price, every piece’s value by its weight, making charges and balances, with no calculator.

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