I have created the chart below that shows some of the different fabric widths available with their corresponding yardage conversion.
To use the chart, look at your pattern and find the yardage needed for the width of the fabric requested. Find the column for the suggested fabric width, move down to the yardage the pattern calls for and then move left or right across the chart to the width of fabric that you are using. For example, if your pattern calls for 2 1/2 yards of 45" wide fabric and you are using 54" wide fabric, you will need 2 yards. If your fabric is only 36" wide, you will need 3 1/8 yards.
Always remember to purchase extra yardage if you are using a plaid or napped fabric (such as corduroy or velvet). Also, if you are using a fabric with a pattern that you plan to incorporate into your design (for example a bird that you want to position on the front of your tote), look at the pattern repeat and direction and plan accordingly; if the fabric motif has a specific direction (as opposed to an all-over pattern), you will need extra fabric because you won’t be able to fit pattern pieces as closely because you can’t turn them upside down.
It is heartbreaking to run out of fabric, especially if you are one that likes to let her fabrics “rest” for awhile before using them (like me) and it is no longer available at the store.
Print this chart out and keep it in your purse so you will have it handy the next time you visit the fabric store. Having this information could save you money, time and anguish.