Jeweler's calculator: add and subtract weights across units
Do weight sums like on a calculator tape, mixing grams, troy ounces and pennyweights without converting by hand. Use it to balance the metal going in and out of the workshop, split a casting or add up invoices in different units.
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Jeweler's calculator
Lines are worked in order, top to bottom, each in its own unit.
Starting weight
14.055 g
In the other units
- Troy ounces
- 0.4519 oz t
- Pennyweights
- 9.038 dwt
- Grains
- 216.9 gr
- Carats (ct)
- 70.276 ct
- Tolas
- 1.2050 tola
How to use the jeweler's calculator
- 1.Enter the first weight and its unit.
- 2.Add lines: add or subtract other weights in whatever unit they come in, or multiply and divide by a number.
- 3.Lines are worked in order, top to bottom, like a calculator tape.
- 4.Choose the unit for the result; it is also shown in every other unit below.
What it is for at the bench
A workshop receives metal in grams, buys findings in pennyweights and reads the gold price in troy ounces. Converting every figure before adding it up is where mistakes creep in.
With the tape you can balance a job: metal issued to the bench, minus finished pieces, minus recovered filings, gives the real loss. Or divide an ingot by the number of pieces to know how much metal goes into each.
Conversions are exact: a troy ounce is 31.1035 g, a pennyweight 1.5552 g, a grain 0.0648 g, a carat 0.2 g and a tola 11.6638 g.
Frequently asked questions
Can I add grams and troy ounces in the same sum?
Yes. Each line carries its own unit; the calculator works in grams internally and gives the result in the unit you choose.
In what order are the lines worked?
Top to bottom, one after another, like a calculator tape: add two weights and then divide by 4, and the whole sum is divided.
How do I work out the metal in each piece of a casting?
Enter the weight of the cast tree, subtract the button and sprue, and divide by the number of pieces.
How many pennyweights are in a gram?
0.643 dwt. The other way round, a pennyweight is 1.5552 g. Choose grams on the first line and pennyweights as the result unit to convert.