When it comes to cooking, correct measurement is a key component. However, between spoons, ounces, grams, pounds, liters and Centigrade, the process can get a little confusing. Here are some basic conversions that will help clarify measurements from the US to metric systems and preserve the joy of cooking. 

The US and metric systems of measurement use the same ounce and pound. Do not confuse the ounce of weight with the fluid ounce, because they are not the same. There is no standard conversion between weight and volume unless you know the density of the ingredient. To make matters worse, there are different kinds of weight measurement; Avoirdupois weight, Troy weight and Apothecaries weight. In the US, when someone refers to pounds and ounces of weight (especially in cooking) they are usually referring to Avoirdupois weight. 

In the metric (SI) system, the term mass is used instead of weight. Weight is a measure of how heavy something is, whereas mass is a measure of the amount of matter. To illustrate, something that weighs 60 pounds on the earth would only weigh about 10 pounds on the moon (due to the lower gravity of the moon), whereas something the has a mass of 60 kilograms on the earth would still have a mass of 60 kilograms on the moon (as the amount of matter is unchanged). 

In the United States, liquid measurement is not only used for liquids such as water and milk, it is also used when measuring other ingredients such as flour, sugar, shortening, butter and spices.

The US uses the Fahrenheit system. The metric system originally used the Celsius temperature system but now officially uses the Kelvin temperature system. However, few people aside from scientists have switched to the Kelvin system and the Celsius system is almost always used by most people for ordinary (non-scientific) purposes. 

The freezing point of water in Fahrenheit is 32°; in Celsius it is 0°.

The boiling point of water in Fahrenheit is 212°; in Celsius it is 100°.

Consequently the difference between freezing and boiling is 180° F (212-32) or 100° C (100-0). This means that 180° change in Fahrenheit is equal to 100° change in Celsius, or more simply 1.8° F equals 1.0° C.