Style guide for metric recipes

Before publishing a metric recipe (whether on paper or the internet) it's a good idea to consult this style guide. Some of these suggestions are based on official recommendations of the Bureau International des Poids et Mesures, the international organization that defines and maintains the metric system. Others are based on a combination of existing practices in metric countries or common sense. Examples are given in the recipes section.

• Liquid ingredients less than 1 liter should be specified in ml, otherwise they should be specified in liters.
• Non-liquid ingredients 1 kg or greater should be specified in kg. Between about 20 and 1000 g they should be specified in grams. Below about 20 g they may be specified by volume to be measured with measuring spoons.
• If using volume to specify non-liquid ingredients larger than about 20 g, then specify the weight in g or kg first, the put the volume in ml or l in parenthesis. For example, 100 g (140 ml).
• All volumes should be specified in ml or l. For small amounts, equivalents in teaspoons or tablespoons may be given in parenthesis, but should not be used alone. For example, 5 ml (1 teaspoon).
• Never use fractions for specifying quantities of ingredients, unless possibly for giving a non-metric equivalent in parentheses.
• Use round numbers when practical. Depending on the accuracy needed for the recipe, numbers may be rounded to the nearest 10, 50, or 100 grams or milliliters.
• List ingredients in the order they will be used.
• Specify temperature in °C. For oven temperatures, the Fahrenheit equivalent should be given in parentheses since many ovens don't have a Celsius scale. For example, 220° C (430° F).
• The Bureau International des Poids et Mesures discourages use of Calories for very good reasons. The correct unit is kilojoules, where 1 Calorie is about 4.186 kJ. If used, Calorie must either always be capitalized or it must be written kilocalorie or kcal. I recommend one of the following styles: 800 kJ (190 Cal) or 800 kJ (190 kcal).
• It is convenient to refer nutritional information to 100 g serving sizes whenever practical for easy comparison of different foods.
• Avoid giving non-metric equivalents for anything except temperature (Fahrenheit) and energy content (Calories). For example, a recipe that gives equivalents in U.S. cups may fail if cooked in the British Isles, and vice-versa. Using metric-only measures ensures that everyone correctly interprets the recipe.
• While the spelling of metric units may vary from country to country, the symbols do not. The symbols should appear exactly as in the table below, with the same capitalization, and should not be written with periods like abbreviations.
• Never use the word "centigrade."
• Be sure to test all recipes before publishing them.

Unit	Symbol
gram	g
kilogram	kg
milligram	mg
liter	l or L
milliliter	ml or mL
meter	m
centimeter	cm
millimeter	mm
kilojoule	kJ
degrees Celsius	°C