21K Gold Purity: Percentage, Stamp & Value Guide
21K = 87.5% gold
21-karat gold contains 87.5% pure gold by weight — 21 parts gold out of 24.
Step by step
- Purity = karat ÷ 24 = 21 ÷ 24.
- 21 ÷ 24 = 0.875 = 87.5%.
- Pure gold in 10 g of 21K = 10 × 0.875 = 8.75 g.
21K is common in the Gulf and Egypt, balancing color and durability.
Details
- Gold content
- 87.5%
- Hallmark stamp
- 875
- Pure gold per gram
- 0.875 g
- Pure gold per troy ounce
- 27.22 g
- Pure gold per tola (11.66 g)
- 10.21 g
How it works
A karat (K or kt) expresses gold purity in 24ths, so the karat number divided by 24 gives the gold fraction. Pure gold is too soft for most jewelry, so it is alloyed with copper, silver, zinc or palladium, which also change the color to rose, white or green gold. The price of a gold item depends on its pure gold weight multiplied by the current gold price, plus workmanship.
Nearby values
Related conversions
Frequently asked questions
How much gold is in 21K?
87.5%.
What is the stamp for 21K gold?
875.
Is 21K gold good for rings?
Yes — it is hard enough for everyday wear.
How do I value 21K gold?
Multiply the weight in grams by 0.875 to get pure gold grams, then by the current gold price per gram.