Quick answer: how to convert pieces to yardage
Start from cut size, not finished size, because seam allowance is already in the cut size. Pieces per strip equal fabric width divided by cut width, rounded down. Strips per yard equal 36 divided by cut length, rounded down. Pieces per yard equal pieces per strip times strips per yard. Strips needed equal pieces needed divided by pieces per strip, rounded up. Total fabric length equals strips times cut length. Yardage to buy is total length divided by 36, rounded up to the nearest 1/8 yard.
Example: a cut rectangle 2.5 by 4.5 inches, 200 pieces needed, fabric width 44 inches. Pieces per strip are 17, pieces per yard are 136, strips needed are 12, total length is 54 inches, exact yardage is 1.50 yards, yardage to buy is 1.50 yards.
Difference from the Fabric Calculator, stated plainly: the Fabric Calculator starts from finished size and adds seam allowance for you, while this calculator starts from cut size and adds nothing. If you enter finished size here, you will undercount, because seam allowance will be missing from every piece. If you are not sure which one you need, use finished size in the Fabric Calculator, and cut size here.
Orientation note: this calculator uses the width you enter across the fabric and the length you enter down the fabric, and it does not automatically test the swapped orientation. If a swapped layout might save fabric, run it once with width and length swapped, and compare the two buy yardages.
If you only need a number, use the Pieces to Yardage Calculator. If you want to understand why pieces per yard is not the same as exact yardage, read on.
What pieces to yardage means
Pieces to yardage means converting a set of cut pieces into yardage to buy. You already know cut piece size, because you already know how you will cut, including seam allowance. You also know how many pieces you need, and fabric width. From those three things, yardage follows, step by step.
This is different from the Fabric Calculator, which starts from finished size and adds seam allowance for you. Pieces to yardage starts from cut size, so no seam allowance is added here. If you only know finished size, use the Fabric Calculator first, then come back here with cut size, if you want to check pieces per yard.
Cut size compared with finished size
| Finished size, with 0.25 inch seam allowance | Cut size |
|---|---|
| 3 by 3 inches | 3.5 by 3.5 inches |
| 2 by 4 inches | 2.5 by 4.5 inches |
| 5 by 5 inches | 5.5 by 5.5 inches |
Cut size is finished size plus seam allowance on both sides. For quilt piecing, seam allowance is usually 0.25 inch, so cut size is finished size plus 0.5 inch in each direction. This calculator uses cut size, because you work from cut size.
Step by step: how to calculate pieces to yardage
Step 1: Work out pieces per strip
Pieces per strip equals fabric width divided by cut piece width, rounded down to the next whole piece. Only whole pieces count, because a partial piece cannot be used. Pieces are cut in strips across fabric width, with strip width equal to cut piece length, and pieces laid side by side across the strip.
Step 2: Work out pieces per yard, for comparison
Strips per yard equals 36 divided by cut piece length, rounded down to the next whole strip, because only whole strips fit in one yard. Pieces per yard equals pieces per strip times strips per yard. Pieces per yard is useful for quick shopping, when you want to know how many pieces one yard gives you, without calculating total yardage first.
Step 3: Work out strips needed
Strips needed equals number of pieces needed divided by pieces per strip, rounded up to the next whole strip. The last strip is only partly used, but you must buy the whole strip, because fabric is bought by length, not by piece.
Step 4: Work out total fabric length
Total fabric length equals strips needed times cut piece length. Total length is the length of fabric you need to cut, from the roll or from yardage, before rounding to yardage to buy.
Step 5: Work out yardage
Exact yardage equals total fabric length divided by 36 in inch mode. Yardage to buy is exact yardage rounded up to the nearest 1/8 yard. In centimetre mode, metres to buy are rounded up to the nearest 0.1 metre.
Try it with the calculator: Use the Pieces to Yardage Calculator with your own cut piece size, piece count and fabric width. It uses the same steps as this guide, and it shows pieces per strip, pieces per yard, strips needed, total length and yardage together.
Worked example: rectangles, not squares
Take a cut rectangle 2.5 by 4.5 inches, pieces needed 200, fabric width 44 inches.
Pieces per strip: 44 divided by 2.5 equals 17.6, rounded down, equals 17 pieces. The leftover width, 44 minus 17 times 2.5, which is 1.5 inches, is not enough for another piece, so it is waste, not an eighteenth piece.
Pieces per yard: strips per yard equals 36 divided by 4.5, equals 8 strips, with no rounding needed. Pieces per yard equals 17 times 8, equals 136 pieces.
Strips needed: 200 divided by 17 equals 11.76, rounded up, equals 12 strips. The last strip gives 17 pieces, but only 13 are needed from it, because 11 strips give 187 pieces, and 200 minus 187 equals 13. The last strip is still only partly used, because it gives 17 pieces and only 13 are needed from it.
Total fabric length: 12 times 4.5 equals 54 inches.
Exact yardage: 54 divided by 36 equals 1.50 yards. Yardage to buy, rounded up to the nearest 1/8 yard, equals 1.50 yards, because 1.50 is already an eighth yard step.
Check by pieces per yard, for sense: 200 pieces divided by 136 pieces per yard equals 1.47 yards, which is close to exact yardage 1.50 yards, but not the same, because pieces per yard rounds strips per yard down, and total length rounds strips needed up. Use total length, not pieces per yard alone, for buying, because total length is exact for your piece count.
Pieces per yard table, our own computed table
This table is computed from the same rule as the calculator, at fabric width 44 inches, and it is not copied from another site. Pieces per yard is a whole-yard count, so it is always lower than pieces per strip times exact strips per yard, because strips per yard is rounded down.
| Cut size | Pieces per strip | Strips per yard | Pieces per yard |
|---|---|---|---|
| 2.5 by 4.5 in | 17 | 8 | 136 |
| 5 by 5 in | 8 | 7 | 56 |
| 2.5 by 2.5 in | 17 | 14 | 238 |
| 10 by 10 in | 4 | 3 | 12 |
How to make sure your result is correct
- Cut versus finished check. Inputs must be cut size, with seam allowance already included, not finished size, or every piece will be too small.
- Pieces per strip check. Pieces per strip must be rounded down. Rounding up would promise a piece that does not fit in the strip width.
- Strips per yard check. Strips per yard must be rounded down, because a partial strip does not fit in a whole yard.
- Strips check. Strips needed must be rounded up. Strips times pieces per strip must be at least pieces needed, never below it.
- Buy versus exact check. Buy yardage must never be below exact yardage, and buy yardage must be a multiple of 1/8 yard.
- Orientation check. If width and length can be swapped, run both orientations and compare buy yardages, because the smaller total wins.
How to count pieces, without missing any
- Count pieces by fabric, not by block alone. A block that uses the same fabric in two places counts twice for that fabric, once for each place.
- Count pieces for the whole quilt top, including borders if the same fabric is used there, and including any extra pieces for testing, if you want a safety margin. Safety margin is your own choice, not part of the calculation, so add it to piece count before calculating, if you want it.
- Check piece count against your pattern, block by block, before buying. A pattern that says 12 blocks, each with 4 pieces of fabric A, means 48 pieces of fabric A, not 12.
Common mistakes with pieces to yardage
- Using finished size as cut size. Finished size does not include seam allowance. Cut size is finished size plus seam allowance on both sides. Using finished size as cut size gives yardage that is too low, and pieces that are too small after sewing.
- Rounding pieces per strip up. Pieces per strip must be rounded down, because only whole pieces count. Rounding up pretends a partial piece is a whole piece, and you will come up short.
- Rounding strips needed down. Strips needed must be rounded up, because you must buy the whole last strip, even if it is only partly used.
- Using pieces per yard alone to buy. Pieces per yard is a guide, not a buying amount, because it rounds strips per yard down. Use total length for your exact piece count, then convert to yardage to buy.
Calculate your own pieces to yardage now
Use your cut piece size, piece count and fabric width in the calculator, and check the result against the steps in this guide.
Open the Pieces to Yardage CalculatorFrequently asked questions
Work out how many cut pieces fit across fabric width, then how many strips you need for your total piece count, then total fabric length, and convert total length to yardage, rounded up to the nearest eighth yard.
Cut size is the size you actually cut, including seam allowance. Finished size is the size a piece will be after it is sewn into the quilt top. This calculator uses cut size, because you work from cut size. If you only know finished size, use the Fabric Calculator, which adds seam allowance for you.
Pieces per yard equals pieces per strip times strips per yard. Strips per yard equals 36 divided by cut piece length, rounded down. For cut rectangles 2.5 by 4.5 inches, with 44 inch fabric, pieces per yard equals 17 times 8, equals 136 pieces.
Yes, but one fabric at a time. Repeat the calculation for each fabric, with that fabric's cut piece size and piece count, and buy each fabric separately.
Because pieces per yard rounds strips per yard down, and total length rounds strips needed up. Pieces per yard is a guide for shopping, but total length for your exact piece count is the amount to buy from.
Related guides and calculators
Next, read How to Calculate Piece Count for pieces from yardage you already own, and How to Calculate Quilt Fabric for yardage from finished size. For pieces to yardage itself, use the Pieces to Yardage Calculator.