To calculate the cost per inch of fabric, divide the price of a yard by 36: that's the cost of one inch of length off the bolt, the full width of the fabric. For the cost per square inch, divide the price of a yard by 36 times the width in inches. Canvas at $14 a yard, 60 inches wide, is about 39 cents an inch of length and about two-thirds of a cent a square inch. Which one to use for a project depends on what happens to the leftovers. In the example below, the canvas pieces of a tote bag use $8.33 of fabric by area, with a waste allowance, but the 51 inches cut off the bolt to get them cost $19.83. If the leftover strip becomes zipper pouches, the bag's fabric cost is $8.33; if it goes in a bin, it's $19.83. Below is the arithmetic, the two methods, the example, and a free calculator.
The short version
- Cost an inch of length = price a yard ÷ 36.
- Cost a square inch = price a yard ÷ (36 × width in inches).
- By area: add up the square inches of every piece, times the cost a square inch, plus a waste allowance.
- By length: the inches cut off the bolt for the project, times the cost an inch.
- Use area when the leftovers go into other products; use length when they don't.
- Long, narrow pieces like straps and gussets are what make the two methods differ.
- TaroStack keeps fabric by the yard and costs every product from its recipe. More below.
The arithmetic
| Fabric | Price a yard | Width | An inch of length | A square inch |
|---|---|---|---|---|
| Canvas | $14.00 | 60 in | $0.389 | $0.0065 |
| Quilting cotton | $12.00 | 44 in | $0.333 | $0.0076 |
| Lining cotton | $9.00 | 44 in | $0.250 | $0.0057 |
| Wide backing | $22.00 | 108 in | $0.611 | $0.0057 |
A yard is 36 inches long, so an inch of length is a thirty-sixth of the price, across the whole width. A square inch also divides by the width. The same idea, a price for one unit and a cost for what you use, is in how to calculate cost per ounce for anything bought by weight.
A tote bag, costed two ways
Driftwood Canvas Co., a made-up maker of canvas bags in Portsmouth, New Hampshire, I use in these examples, cuts a tote bag's canvas from 60-inch canvas at $14 a yard:
| Piece | Width | Length | How many | Square inches |
|---|---|---|---|---|
| Body panel | 17 in | 19 in | 2 | 646 |
| Gusset | 5 in | 51 in | 1 | 255 |
| Strap | 4 in | 27 in | 2 | 216 |
| Total | 1,117 |
By area: 1,117 square inches at $0.0065, plus 15% for the bits between pieces, is $8.33. How a waste allowance works is in scrap rate formula.
By length: laid side by side across the 60-inch width, the pieces need 51 inches off the bolt, because the gusset is 51 inches long. That's $19.83 of canvas, and the bag uses only 37% of it. The rest is a strip about 13 inches wide and 51 long, plus the space under the shorter pieces.
Which one to use
If the leftover strip becomes zipper pouches, card holders or patches, the bag's fabric costs $8.33 and the pouches carry their own share: two 10 by 8 inch panels are 160 square inches, about $1.19 of canvas with the allowance, and the strip holds three pouches. If it ends up in a scrap bin, the bag's fabric costs $19.83, and pricing it at $8.33 loses $11.50 on every bag. In practice it's often somewhere between, so the honest move is to cost by area only for the leftovers you really use. Then put the full cost into the price; how is in how to price handmade items.
Get the calculator
Download the fabric cost calculator. Type the fabric's price a yard and its width, and it works out the cost an inch of length and a square inch. List each piece you cut, its width, length and how many, and type the inches you cut off the bolt; it works out the project's fabric cost by area, with your waste allowance, and by length, and what share of the cut fabric the pieces use. It's an ordinary Excel file with no macros, and it works in Google Sheets, LibreOffice and Numbers.
Where this stops working
One project on one fabric is easy. A maker with a dozen canvases and cottons, bought by the bolt at different prices, making bags, pouches and aprons from the same rolls, can't keep the leftovers straight, or say what's left on a bolt before cutting a big order.
How TaroStack does it
TaroStack keeps fabric by the yard and every product costed from its recipe.
Fabric by the yard. Each fabric is an item kept at what you paid, and units convert: fabric bought by the bolt, used by the inch. A product is a recipe of its fabrics, thread, labels and hardware, with a scrap % for what the layout leaves.
Each run at what it used. Recording a run of bags takes the fabric off stock at what you paid, so the cost of a bag follows the price of canvas, and margins are reported by product. Leftover strips can be kept as their own item and used in the pouch recipe.
And the bolts before an order. Stock is counted on a phone, wholesale orders are sales orders that show whether the canvas to fill them is on the shelf while you're still typing, and the reorder list works in days of cover.
| The job | Notebook | In TaroStack |
|---|---|---|
| Canvas left on a bolt | Unroll and measure | Yards on hand |
| What a bag's canvas cost | Worked out once | Each run, at what it used |
| Leftovers into pouches | Not tracked | Their own item, in the pouch recipe |
| Bags or pouches, which pay? | A feeling | Margins by product |
Recipes, batches, counting and margins by product are on every plan, from $49 a month. The first 30 days are free, with no credit card. If you'd like a hand setting up, ask, and we'll do it with you.