Quick answer: how to calculate piece count
Start from cut size, not finished size, because seam allowance is already in the cut size. Total fabric length you own equals yardage times 36 inches. Pieces per strip equal fabric width divided by cut width, rounded down. Strips you can cut equal total length divided by cut length, rounded down. Total pieces equal pieces per strip times strips. Leftover length equals total length minus strips times cut length, and leftover width equals fabric width minus pieces per strip times cut width.
Example: yardage you already own 1.5 yards, cut piece 4 by 5 inches, fabric width 44 inches. Total length is 54 inches, pieces per strip are 11, strips are 10, total pieces are 110, leftover length is 4 inches, leftover width is 0 inches.
Difference from Pieces to Yardage, stated plainly: Piece Count starts from yardage you already own and gives a count, while Pieces to Yardage starts from a count you need and gives yardage to buy. Both use cut size, both round down, and neither automatically tests the swapped orientation. If a swapped layout might fit more pieces, run it once with width and length swapped, and compare the two counts.
If you only need a number, use the Piece Count Calculator. If you want to understand why area division overcounts, read on.
What piece count means
Piece count means how many cut pieces you can cut from fabric you already own. It is the inverse of pieces to yardage. Pieces to yardage starts from pieces needed and works out yardage to buy. Piece count starts from yardage already owned and works out pieces that can be cut.
Piece count is useful when you have a stash, a fat quarter, a yard cut, or a leftover piece, and you want to know if it is enough for a block, a row, or a whole quilt, before you cut. It is not a buying calculation, because it counts pieces from fabric you already have, it does not buy fabric.
Why piece count is rounded down, twice
| Step | Rounding | Why |
|---|---|---|
| Pieces per strip | Round down | A partial piece cannot be cut across fabric width |
| Strips you can cut | Round down | A partial strip cannot be cut along the roll |
| Total pieces | Multiply, no rounding | Pieces per strip times strips, both already whole numbers |
Rounding up at either step would count pieces you cannot actually cut. Rounding down at both steps means piece count is always a safe count, not an optimistic count. Leftover fabric is not lost, it is simply not enough for one more whole piece in this layout.
Step by step: how to calculate piece count
Step 1: Work out total fabric length you own
Total fabric length you own equals yardage owned times 36, because one yard equals 36 inches. For yardage owned 1.5 yards, total fabric length you own equals 1.5 times 36, equals 54 inches.
Step 2: Work out pieces per strip
Pieces per strip equals fabric width divided by cut piece width, rounded down to a whole number, because a partial piece cannot be cut. For fabric width 44 inches and cut piece width 4 inches, pieces per strip equals 44 divided by 4, equals 11 pieces, exactly, with no leftover width.
Step 3: Work out strips you can cut
Strips you can cut equals total fabric length you own divided by cut piece length, rounded down to a whole number, because a partial strip cannot be cut. For total length 54 inches and cut piece length 5 inches, strips you can cut equals 54 divided by 5, equals 10.8, rounded down to 10 strips.
Step 4: Work out total pieces you can cut
Total pieces you can cut equals pieces per strip times strips you can cut. For pieces per strip 11 and strips 10, total pieces you can cut equals 11 times 10, equals 110 pieces.
Step 5: Work out leftover fabric
Leftover length along the roll equals total fabric length you own minus strips you can cut times cut piece length. For total length 54 inches and strips 10 times cut length 5 inches, leftover length equals 54 minus 50, equals 4 inches. Leftover width per strip equals fabric width minus pieces per strip times cut piece width. For fabric width 44 inches and pieces per strip 11 times cut width 4 inches, leftover width equals 44 minus 44, equals 0 inches per strip.
Try it with the calculator: Use the Piece Count Calculator with your own yardage, cut piece size and fabric width. It uses the same steps as this guide, and it shows total fabric length you own, pieces per strip, strips you can cut, total pieces, and leftover fabric, together.
Worked example: 1.5 yards, cut 4 by 5 inch pieces
Take yardage you already own 1.5 yards, cut piece 4 by 5 inches, fabric width 44 inches.
Total fabric length you own: 1.5 times 36 equals 54 inches.
Pieces per strip: 44 divided by 4 equals 11 pieces, exactly, with no leftover width.
Strips you can cut: 54 divided by 5 equals 10.8, rounded down to 10 strips.
Total pieces you can cut: 11 times 10 equals 110 pieces.
Leftover length along the roll: 54 minus 10 times 5, equals 4 inches. Leftover width per strip: 44 minus 11 times 4, equals 0 inches per strip.
In this example, leftover length 4 inches is not enough for one more 5 inch strip, so it is waste for this piece size, unless a smaller piece can use it. Leftover width 0 inches means the strip layout is exact across fabric width, with no side waste.
Area division trap table, our own computed table
This table uses one yard of fabric, 44 inches wide by 36 inches long, and shows why dividing areas overcounts. Area count equals fabric area divided by piece area, rounded down, but that ignores that a partial piece cannot be cut. Real count equals pieces per strip times strips, both rounded down. It is computed from the same rule as the calculator, not copied from another site.
| Square cut size | Real grid count per yard | Area division claim | Overcount |
|---|---|---|---|
| 2.5 in | 238 | 253 | 15 |
| 5 in | 56 | 63 | 7 |
| 10 in | 12 | 15 | 3 |
Never buy or plan from the area count. Plan from the grid count, because only whole pieces can be cut.
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.
- Round down twice check. Pieces per strip must be rounded down, and strips must be rounded down. Rounding either up would promise a piece or a strip that does not fit.
- Total check. Total pieces must equal pieces per strip times strips, never pieces per strip times exact strips, and never area divided by piece area.
- Leftover check. Leftover length must be less than one cut length, and leftover width must be less than one cut width, or another strip or piece would fit and the count is wrong.
- Orientation check. If width and length can be swapped, run both orientations and compare counts, because the larger count wins, and directional prints must not be rotated.
When piece count is enough, and when it is not
- Piece count is enough when: you need cut pieces in the stated layout, with cut piece width across fabric width and cut piece length along the roll, and you will check piece count before cutting.
- Piece count is not enough when: your fabric has a directional print and pieces must all run one way, your pieces must be cut in a specific orientation, or your pieces are not rectangles. In those cases, check piece layout before cutting, and do not rely on piece count alone.
- Piece count does not fix a wrong cut size: if you use finished size instead of cut size, piece count will be too high, because finished size is smaller than cut size. Use cut size, which already includes seam allowance, in the calculator.
Common mistakes with piece count
- Using finished size as cut size. Finished size is smaller than cut size, because cut size already includes seam allowance. For example, a finished 3.5 inch piece, with 0.25 inch seam on each side, is cut 4 inches. Use cut size, not finished size, in the calculator.
- Rounding piece count up. Piece count must be rounded down at pieces per strip and at strips, because a partial piece cannot be cut. Rounding up would count pieces you cannot actually cut.
- Dividing total area by piece area. Total area divided by piece area gives a higher count than strip layout, because it ignores leftover width and leftover length. Strip layout is the real count, area division is an optimistic count.
- Counting pieces for the whole quilt at once. Count pieces by fabric, not by quilt, if different fabrics use different piece sizes. Adding piece counts for different fabrics into one count gives the wrong count for each fabric.
Calculate your own piece count now
Use your yardage owned, cut piece size and fabric width in the calculator, and check the result against the steps in this guide.
Open the Piece Count CalculatorFrequently asked questions
Multiply yardage by 36 to get total length in inches, divide fabric width by cut piece width and round down to get pieces per strip, divide total length by cut piece length and round down to get strips, then multiply pieces per strip by strips to get total pieces. For example, 1.5 yards of 44 inch fabric, cut 4 by 5 inch pieces, gives 11 pieces per strip, 10 strips, and 110 pieces total.
Pieces to yardage starts from pieces needed and works out yardage to buy. Piece count starts from yardage already owned and works out pieces that can be cut. They are inverses of each other, and they use the same strip layout, with rounding down in both directions.
Piece count is rounded down at pieces per strip and at strips, because a partial piece cannot be cut. Rounding up would count pieces you cannot actually cut.
Use cut size, not finished size, because cut size already includes seam allowance. For example, a finished 3.5 inch piece, with 0.25 inch seam on each side, is cut 4 inches.
No. Piece count assumes rectangular pieces, cut in the stated layout, with cut piece width across fabric width and cut piece length along the roll. For triangles, circles, or other shapes, check piece layout before cutting, and do not rely on piece count alone.
Related guides and calculators
Next, read How to Calculate Pieces to Yardage for yardage from pieces needed, and How to Calculate Fat Quarter and Precut Pieces for pieces from precuts. For piece count itself, use the Piece Count Calculator.