Most ranges have dials that display the cooking temperature of the oven.  In North America, most of these temperatures are written in Fahrenheit and usually are in increments of 25°.  In Canada, recipe and oven temperatures are often presented in degrees Celsius.  It is important then to understand how to convert a Fahrenheit temperature to an appropriate Celsius temperature.  For example, let’s say your oven displays Fahrenheit temperatures with 50° increments.  Your recipe tells you to bake your dish at 220°C.  What temperature do you turn your oven to?  Well, you will need to convert 220°C to a Fahrenheit measurement.

We use this formula to convert Celsius to Fahrenheit:

To make sure you do not over bake the cookies, you will need to set the oven to 428°F.  But remember, your oven only displays the temperature in 50° increments, so you must estimate on the dial where 428°F is, somewhere between 400°F and 450°F. The relationship between celsius and fahrenheit is a linear function:

We also use conversions when we bake or cook to convert sizes and amounts.  Many recipes are written in imperial units (teaspoon, tablespoons, and cups).  Some newer recipes and measuring devices in Canada are labeled in metric units, such as milliliters (mL).  If the recipe calls for ½ cup of butter and your measuring equipment is labeled in mL, how will you know which measurement to use?  We can apply this conversion formula: 1 cup = 237mL.  This means that ½ cup = 118.5mL.  Again, this exact measurement is probably not on the measuring cup.  It is probably closest to 125mL, so we will again have to estimate.