gram, g (gram)

The gram is a unit in the metric system. When no specific figure is stated, write gram or grams in full.

• How many grams of fat are you allowed on your diet plan?

When a specific figure is given, leave a space between the word gram (or the symbol g) and the number that immediately precedes it. In scientific and technical writing, either the number and unit name are both written in full (e.g. twelve grams), or a numeral is used with the symbol (e.g. 12 g).

• Foster added precisely three grams of sodium chloride to the liquid in the test tube.
• Whitney needed another 250 g of sugar for the jam recipe.

However, general usage accepts numerals with spelled-out unit names to improve comprehension.

• One pound is just over 450 grams.

Symbol g

The unit symbol g is always in lower case, even when the rest of the text is in upper case, as in a newspaper headline.

• Headline: BORN WEIGHING 400 g, BABY THRIVING

Note: Because the metric system uses symbols and not abbreviations, there are no periods or plural forms for symbols; gm and gms are non-standard short forms.

Gram as a modifier

For the sake of clarity, when gram or g is used as a modifier, a hyphen is inserted between the numeral and the unit name or the symbol.

• A one-gram difference in weight is negligible.
• The 50-g mouse outsmarted the 7-kg cat every time.