Fat Quarter Calculator and Cutting Chart

What size is a fat quarter?

A fat quarter starts from a half yard, which measures 18 x 44 in, and is cut in half across the width. The result is about 18 x 22 in. Fabric makers often describe a fat quarter as 18 x 21 in, because once you remove the selvages and square up the piece, about 21 in of the width is left to use. Fat Quarter Shop lists its bundles at 18 x 21 in, and this tool uses the same size by default.

In centimeters, that is about 45 x 55 cm before trimming. Your own fat quarters may be slightly different, especially if they were prewashed or cut by hand. Measure one if your plan is tight, and change the usable width and height in the tool. A quarter inch here or there can decide whether a row fits.

Fat quarter or quarter yard: which is bigger?

They hold the same amount of fabric, but they are very different shapes. A regular quarter yard is a long strip of 9 x 44 in. A fat quarter is a shorter, wider rectangle of 18 x 22 in, and that shape is what makes it useful. You can cut an 8 1/2 in square, or even a 10 in square, from a fat quarter, while a regular quarter yard cannot give you anything wider than 9 in.

A quarter yard can be better for some cuts, though. Long strips, such as borders or binding, are easier to cut from yardage, since you avoid so many joins. If your pattern calls for strips cut across the width of fabric, a fat quarter will only give you strips about half as long. You would need twice as many strips, and you will have more seams. Check the pattern before you swap one for the other.

How to get the most from a fat quarter

The number of pieces depends on how neatly they divide into the 18 x 21 in rectangle. A 5 in square fits 3 across and 4 down, for 12 squares, and it leaves a useful strip along two sides. A 6 1/2 in square gives only 6, since 2 fit across and 3 down, and it leaves more waste. If a pattern lets you choose your block size, try a few in the tool and compare the percentage used.

Rectangles can often be turned to fit better, and the tool always checks both directions. If you are fussy cutting, or your print has a clear direction, you will need to think about that yourself, since turning the piece also turns the print. For directional prints, cut with the print running the way you need, and enter the width and height so that they match. You may get fewer pieces, but they will all face the right way.

How many fat quarters do I need for a quilt?

That depends on the block and the quilt size, which is why this tool starts with the pieces you need. As a rough guide, a throw quilt in a simple pattern usually takes about 16 to 24 fat quarters, and a queen often takes 36 or more. Patterns that add a lot of background fabric, sashing or borders will need fewer fat quarters and some extra yardage instead.

To work it out properly, first find how many pieces your quilt needs. A 50 x 65 in throw made of 5 1/2 in cut squares, which finish at 5 in, needs 10 across and 13 down, or 130 squares. Each fat quarter gives 9 squares of that size, since 3 fit across and 3 fit down. So you need 130 divided by 9, which rounds up to 15 fat quarters. It is easy to try this with your own pattern, using the quilt size chart to choose the size.

Using fat quarter bundles well

Bundles are a low-risk way to collect a whole fabric line, since the prints are designed to work together. Before you cut, sort them into lights, mediums and darks. A quilt needs that range of values to show its pattern clearly, and a bundle of similar values can look flat from a distance. Pull out any print you do not love and swap in something from your stash.

Press your fat quarters before you cut, using a little starch if the fabric has been folded for a long time. Then square up one edge with your ruler and rotary cutter. If you need a lot of the same piece, you can layer two or three fat quarters and cut them together, as long as your blade is sharp. Keep any useful leftovers, because strips and squares from a good bundle are ideal for binding, scrappy blocks or small projects.

Common fat quarter mistakes to avoid

A very common mistake is assuming that all fat quarters are the same size. Hand-cut pieces can vary by half an inch or more, and some have been trimmed before they were sold. Measure one before you settle on a tight cutting plan, and change the size in the tool if yours is smaller. Another mistake is forgetting the grain. The long side of a fat quarter usually runs across the bolt, and the short side runs along it. The lengthwise grain has less stretch, so keep this in mind if you are cutting long, narrow pieces.

It is also easy to plan for the theoretical maximum and leave no room for error. If your plan needs every last inch, one slip with the rotary cutter can mean that you are a piece short. Allow one spare fat quarter on a large project, particularly if you cannot get more of a print. When you do cut, always square up one edge first. If you skip this, the cuts that follow can drift off the grain, and the blocks will not sit flat. Finally, cut the largest pieces first, then use what is left for the smaller ones.