Gram Abbreviation: How to Write g

Gram abbreviation basics: g, lowercase, no period

The metric system sets fixed symbols for its units, and the gram's is g. Three rules cover almost every case:

1. Keep it lowercase. A capital G is the prefix giga, as in GB for gigabytes. It never means gram.
2. Skip the period. Metric symbols are not followed by a period unless they end a sentence.
3. Do not add an s. 5 g means five grams. The symbol does not change for the plural.

Spelled out, the word does change: one gram, two grams. So "grams abbreviation" and "abbreviation for grams" both lead to the same answer, g.

Grams on recipes and nutrition labels

American recipes mostly use cups and spoons, but baking recipes and many imported cookbooks weigh ingredients in grams for accuracy.

US Nutrition Facts labels list fat, carbohydrates, sugar and protein in grams, and smaller nutrients such as sodium in milligrams. Labels often print the number and the g with no space, such as "Protein 8g." That is the label layout; in your own writing, the standard form is 8 g with a space. To switch between systems, remember that one ounce is about 28.35 grams and one pound is about 454 grams.

The gram family: kg, mg and mcg

Each prefix multiplies or divides the gram by a power of ten. The milligram and microgram have their own pages: mg and mcg. In medicine, writers often use mcg instead of µg because the Greek letter can look like an m and lead to a dose that is a thousand times too large.

Abbreviations for gram to avoid

• gm or gms: once common on labels and in some kitchens, but not the standard symbol. Many medical style guides advise against it.
• gr: the abbreviation for grain, an old unit still seen on some medicine and ammunition labels. One grain is about 65 milligrams, so mixing up gr and g can cause a big error.
• Gm or G: capitals belong to other units and prefixes.
• g. with a period: not used in metric style unless the sentence ends there.

If a label uses gm, it still means gram, but in your own writing stick with g. For other clipped and shortened words, see the common abbreviations list.

Writing grams in sentences

• "Each bar has 12 g of protein."
• "Add 200 g of sugar and mix until smooth."
• "The letter weighed 28 g, just under one ounce."
• "The sample had a mass of 3.5 g."
• "Several grams of salt spilled on the counter." (Spell it out when no number comes before it.)

Use the symbol with a numeral and the full word when the amount is written in words or left vague: "a few grams," "two grams of yeast." At the start of a sentence, spell out both the number and the unit.