Fine gold calculator, from tunch
Type the gross weight and the tunch to see the fine gold in it. If you settle at tunch plus wastage, add the wastage and see how much fine gold it adds.
Weight × tunch ÷ 100 What the scale shows, without stones.
The purity from a touch or XRF test, or the tunch agreed with the party.
Leave 0 if there is none. Some parties settle at tunch + wastage, like 91.6 + 0.5.
Fine gold
9.160 g
10.000 g at 91.6% · fine gold 9.160 g
- Fine gold at the tunch
- 9.160 g
- Added by the wastage
- 0.000 g
- Tunch used
- 91.6%
- Fine gold
- 9.160 g
Rounded to the milligram. Settle with the party at the tunch you both agree.
Run a jewellery shop? Read the karigar guide
How it's worked out
How fine gold is worked out from tunch
Tunch (or touch) is purity as a percentage: how much of the weight is pure gold. Fine gold is the gross weight × the tunch ÷ 100.
When a party settles at tunch plus wastage, the two are added first, and the fine gold is worked out at that figure. The extra fine gold is the wastage.
For fine weight by karat, use the purity converter. To value old gold at a fine rate, use the old gold exchange calculator.
22K bangles · 50 g · 91.6 + 0.5 Worked example
An example, step by step
A karigar returns 22K bangles that weigh 50 g. You settle at a tunch of 91.6% plus 0.5% wastage.
- 1 Fine gold at the tunch 50 g × 91.6% 45.800 g
- 2 Tunch + wastage 91.6% + 0.5% 92.1%
- 3 Fine gold to settle 50 g × the two together 46.050 g
The difference, 0.250 g, is the wastage, in fine gold.
CaratOS for your shop
Karigar metal, kept in fine weight.
In CaratOS, karigar jobs record the metal given and back by weight and purity, on every plan. On Growth, wastage is worked out against the allowance you set, in fine weight.
Your 15-day Starter trial begins when CaratOS approves your request. No card needed.
- Gross weight back
- 48.250 g
- Purity
- 22K (916)
- Fine gold back
- 44.229 g
Questions about tunch and fine gold
Tunch, also called touch, is the purity of gold or silver as a percentage: how much of the weight is pure metal. Hallmarked 22K gold is 916, or 91.6%; 18K is 750, or 75%.
Gross weight × tunch ÷ 100. For example, 10 g at a tunch of 91.6% has 9.160 g of fine gold.
Some jewellers and karigars settle by adding the wastage to the tunch, for example 91.6 + 0.5 = 92.1%. The fine gold is then worked out at 92.1%, so the extra is the wastage, already in fine gold.
They measure the same thing in different ways. Karat counts parts of 24; tunch is a percentage. The hallmark grade for 22K is 916, or 91.6%. A touch or XRF test can read a little different from the stamp, which is why many jewellers settle on the tested tunch.
Yes, the maths is the same. 100 g of silver at a tunch of 92.5% has 92.500 g of fine silver.
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More calculators
Jewellery wastage calculator
Wastage as a % or grams: the metal it adds, its fine gold and value. Open the calculator
Old gold exchange calculator
What old gold is worth: weight × tested purity × the old gold rate. Open the calculator