Precut Fabric Calculator
Enter the square size you want to cut and how many you need. The calculator tells you how many fit across the fabric, how many yards to buy, and how many fat quarters that equals.
Tip: use URL parameters to pre-fill, e.g. ?squareSize=5&squareCount=60.
How precut math works
Divide the usable fabric width (42 inches) by your square size and round down to get the number of squares across one strip. Divide the count you need by that number and round up to get the number of strips, then multiply by the square size and divide by 36 for yards.
For fat quarters, the same idea uses the 18 x 22 inch rectangle: squares across times squares down. A 5-inch charm square yields 3 x 4 = 12 squares per fat quarter.
Common precut sizes
| Precut | Size | Approx. per yard (42") | Per fat quarter |
|---|---|---|---|
| Mini charm | 2.5" | 224 | 56 |
| Charm pack | 5" | 56 | 12 |
| Layer cake | 10" | 12 | 2 |
| Jelly roll strip | 2.5" x WOF | 14 strips | n/a |
What each input means
Square size: the cut size of the square before any seam allowance. For finished squares, add 1/2 inch first.
Squares needed: how many squares your project requires. The calculator rounds up to whole strips and whole fat quarters.
The calculator assumes a 42-inch usable fabric width for the yardage answer — the standard cutting width of 44-45 inch quilting cotton after the selvedges are removed. Fat quarter answers assume an 18 × 22 inch precut; if your fat quarters are cut differently, adjust the numbers proportionally or use the fat quarter calculator on this site with your actual dimensions. Whole-square layouts also assume you can nest pieces edge to edge with no gaps.
Common mistakes to avoid
- Entering finished sizes instead of cut sizes. A charm square is cut at 5" and finishes at 4.5" once sewn; enter the cut size unless your pattern states finished.
- Using the full 44-45 inch width. Selvedges are unusable; 42 inches is the honest planning number and keeps your strips from coming up short.
- Rounding strips down. If 56 squares need 7 strips, buying for 6 leaves you short — the calculator rounds up for you.
- Assuming every fat quarter is 18 × 22. Some shops trim to 18 × 21 or less; measure yours before planning a layout that depends on exact counts.
- Ignoring directional prints. One-way motifs can't be rotated for nesting, which reduces the number of squares per strip.
When to use it. Use this calculator when a pattern asks for a number of charm, layer-cake or custom squares and you're shopping from yardage or fat quarters. It answers the two questions that decide your purchase — how many squares fit across the fabric and how many yards or fat quarters cover your total — so you can compare precuts against yardage before you buy. If your pattern uses a different precut, like a mini charm pack or a half-yard cut, the same math applies: divide each dimension of the fabric by the square size, multiply the results, and round up to whole strips or precuts.
Common questions
Why use 42 inches as the fabric width?
Most 44-45 inch quilting cottons lose 2-3 inches to selvedges, leaving about 42 inches of usable width. Using the true width avoids short strips.
Is a layer cake exactly 10 inches?
Layer cakes are cut at 10 inches before any seam allowance, so they finish at 9.5 inches in a quilt. The same rule applies to charm squares and other precuts.
How many jelly roll strips make a quilt?
A typical jelly roll has 40 strips, enough for a modest lap quilt when sewn into a strip set. The exact count depends on your pattern and finished size.
Should I add fabric for shrinkage with precuts?
Precuts are usually not prewashed by the manufacturer, so they can shrink in your first wash. Add 3-5% to your yardage estimate if you plan to wash the finished quilt.
Can I use this for triangles or rectangles?
This calculator handles squares. For rectangles, split the piece into its dimensions and use the fabric yardage calculator on this site.