What is ounce?
An ounce is a unit of mass in imperial and US customary systems equal to approximately 28.35 grams. It is frequently used in cooking, food portioning, and the measurement of precious metals.
Real-world uses
Ounces are used in the US and UK for food packaging, postal weights, and cooking recipes. Precious metals are weighed in troy ounces (slightly heavier than avoirdupois ounces) on commodity exchanges worldwide.
History
The word "ounce" comes from the Latin "uncia," meaning one-twelfth (of a Roman pound). The avoirdupois ounce became standard in English trade by the 14th century, defined as 1/16 of an avoirdupois pound.
Common mistakes
Confusing avoirdupois ounces (28.35 g, used for general weight) with troy ounces (31.10 g, used for precious metals) or fluid ounces (a volume measure). These are three distinct units sharing the name "ounce."
What is gram?
A gram is a metric unit of mass equal to one thousandth of a kilogram. It is widely used in cooking, food labelling, and the measurement of small quantities in science and pharmacy.
Real-world uses
Grams are used for food nutrition labelling, postal weight limits, cooking recipes (especially in baking where precision matters), and jewellery weights. Pharmacists measure drug dosages in grams and fractions thereof.
History
The gram was the original base unit of mass in the French metric system of 1795, defined as the mass of one cubic centimetre of water. It later became the base unit in the CGS system before the kilogram took precedence in SI.
Common mistakes
Confusing grams with grains (1 grain ≈ 0.065 g), a common error in pharmaceutical contexts. Also, mistaking "g" for "G" in digital contexts where G means giga.
When is this conversion used?
Converting between ounce and gram is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region. Cooking recipes and food packaging often switch between grams and ounces, especially when adapting recipes from different culinary traditions.
Worked examples
1 ounce = 28.34952313 gram
1 gram = 0.001 kilogram
How to convert ounce to gram
To convert ounce to gram, multiply the value by 28.34952313.
To convert gram back to ounce, multiply by 0.03527396.
Measurement standards
The kilogram is defined by fixing the Planck constant to exactly 6.62607015 × 10⁻³⁴ joule-seconds, as established at the 26th General Conference on Weights and Measures in 2018. This ended the last SI definition based on a physical artefact.
Did you know?
The International Prototype of the Kilogram, a platinum-iridium cylinder stored near Paris since 1889, was found to have drifted by about 50 micrograms relative to its copies over a century — roughly the mass of a fingerprint.
Quick reference: ounce to gram
| ounce | gram |
|---|---|
| 0.1 | 2.83495231 |
| 0.5 | 14.17476156 |
| 1 | 28.34952313 |
| 2 | 56.69904625 |
| 5 | 141.74761563 |
| 10 | 283.49523125 |
| 25 | 708.73807813 |
| 50 | 1,417.47615625 |
| 100 | 2,834.9523125 |
| 250 | 7,087.38078125 |
| 500 | 14,174.7615625 |
| 1,000 | 28,349.523125 |
Common values
| ounce | gram | |
|---|---|---|
| A paperclip | 35.27396195 ounce | 1,000 gram |
| A smartphone | 6,172.94334118 ounce | 175,000 gram |
| A bag of sugar | 35.27396195 ounce | 1,000 gram |
| Average adult human | 2,469.17733647 ounce | 70,000 gram |
| A small car | 42,328.7543395 ounce | 1,200,000 gram |