What's the difference between troy and avoirdupois ounces?

Troy ounces are used for precious metals and gems (1 troy oz = 31.1 g). Avoirdupois ounces are common for everyday items (1 oz = 28.35 g). See [ounces to grams](/weight/ounces-to-grams/) for the reverse conversion.

How is gemstone weight measured?

Gemstones are weighed in carats (1 carat = 200 mg = 0.2 g). One carat equals 0.007 troy ounces.

I'm buying gold jewelry. A ring is listed as 14 grams. How many ounces is that?

14 grams ≈ 0.49 ounces (avoirdupois) or 0.45 ounces (troy). For precious metals, troy ounces are standard, so always check which type is being used. For larger weights, see [kg to lbs](/weight/kg-to-lbs/).

Why are there different types of ounces for different items?

Historical reasons. Precious metals historically used troy weight for accuracy in trade. Regular goods use avoirdupois. Today, both systems coexist depending on the industry.

Grams to Ounces Converter

Enter a value to instantly convert between weight units.

From

Precision4 dp

1 Gram = 0.0353 Ounce

Key Formulas

Kilogram → Pound

lb = kg × 2.20462

Pound → Kilogram

kg = lb × 0.453592

Gram → Ounce

oz = g × 0.035274

Ounce → Gram

g = oz × 28.3495

Formula

oz = g × 0.03527396

Grams are the metric unit for small weights used in jewelry, gemology, and precious metals. Ounces are common in English-speaking countries for measuring small quantities. You'll convert between these when buying diamonds, gold, or comparing gemstone weights from different suppliers worldwide.

Source: NIST SP 811, Table B.8

Frequently Asked Questions

Real-World Examples

28.35 grams equals exactly 1 avoirdupois ounce

28.35 g = 1 oz

A typical 5-gram gemstone weighs about 0.18 ounces

5 g = 0.176 oz

1 troy ounce (for precious metals) is 31.1 grams, slightly different from avoirdupois

31.1 g = 1.098 oz

100 grams is a common ingredient or product weight; equals about 3.5 ounces

100 g = 3.527 oz

kg to lbs lbs to kg ounces to grams kg to grams stone to kg

Grams to Ounces Converter

Key Formulas

Formula

Frequently Asked Questions

Real-World Examples

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