Convert grams to ounces

グラム

定義

A gram (symbol: g) is the SI unit of mass, defined as one-thousandth of a kilogram—the SI’s base mass unit. Since 2019, the kilogram itself is tied to a fixed value of Planck’s constant, so the gram inherits that precise, artifact-free definition.

歴史的背景

Originally, a gram was conceived as the mass of one cubic centimetre of water at the melting point of ice (4 °C). It formed part of the old CGS (centimetre-gram-second) system until the SI unified mass under the kilogram. Today, a gram remains exactly 0.001 kg.

今日の使い方

Grams are ubiquitous in cooking, nutrition labeling (per 100 g), scientific measurements, and everyday commerce worldwide.

オンス

定義

An ounce (symbol: oz) belongs to the imperial and U.S. customary systems. The international avoirdupois ounce is precisely 28.349523125 g, or one-sixteenth of an avoirdupois pound.

歴史的背景

Its name derives from the Roman ウンシア (“twelfth part”), when a copper bar—defining both the Roman pound and foot—was split into twelve equal unciae. Over centuries, regional “ounces” varied (Dutch 100 g, French ~30.59 g, Spanish ~28.75 g) until the modern avoirdupois ounce was ratified in 1959.

今日の使い方

Ounces remain standard in the U.S. for food packaging, portion sizes, postal rates, and more. Although the U.K. has officially metricated, you’ll still see ounces in restaurant menus and some retail contexts.

Grams → Ounces Conversion Table

• 1 g = 0.03527396 oz

• 1 oz = 28.349523125 g

例

Convert 15 g to ounces:

15 g × 0.03527396 = 0.5291094 oz