Cloth Cover Calculator
Bookcloth dimensions from board size and turn-in allowance.
About this calculator
A case binding's cloth has to cover more ground than most binders expect on their first book: it wraps the front board, the spine piece, the back board, a flexible joint gap on each side of the spine, and then folds back over every edge as the turn-in. This calculator lays all of that out edge to edge — cloth width = turn-in + board width + joint gap + spine width + joint gap + board width + turn-in, and cloth height = board height + (2 × turn-in) — using a fixed 7 mm joint gap on each side of the spine, the middle of the standard 6–8 mm range that lets the cover hinge open without cracking the cloth. The turn-in allowance, how far the cloth folds over each board edge before being glued down, is adjustable from 10 to 30 mm; 15–20 mm is the conventional range for hand binding.
Beyond the raw cut dimensions in millimeters and inches, the calculator also estimates yardage from a standard 112 cm (44 in) bookcloth roll: it figures out how many cover pieces fit side by side across the roll's width, how many rows of that many are needed to cover your full run of books, and converts the resulting roll length into yards for ordering. One thing to watch: the spine width isn't computed here — it's a separate input you're expected to pull from a book block or spine-width calculator first, since spine thickness depends on page count, paper caliper, and sewing method, none of which this tool touches.
Inputs
Results
Cloth width (mm)
371
Cloth height (mm)
256
How to Use This Calculator
- Enter the height and width of each cover board in millimeters (board height = block height + overhang).
- Enter the spine width in mm — use the Book Block Calculator to determine this value.
- Set the turn-in allowance in mm (the amount of bookcloth that folds over the board edges); 15–20 mm is standard.
- Enter the number of books to calculate total cloth for a production run.
- Read the cloth width and height in mm (and inches) — these are the cut dimensions for your bookcloth.
- Use the roll length in yards to order from a standard 44-inch wide roll of bookcloth.
How the result changes with Board width (mm)
| Board width (mm) | Cloth width (mm) | Cloth height (mm) |
|---|---|---|
| 76 | 221 | 256 |
| 113 | 295 | 256 |
| 227 | 523 | 256 |
| 378 | 825 | 256 |
What each input means
- Board height (mm)
- Height of each cover board in mm (block height + overhang).
- Board width (mm)
- Width of each cover board in mm (block width + overhang).
- Spine width (mm)
- Width of the spine piece (use the Book Block Calculator to determine this).
- Turn-in allowance (mm)
- How far the cloth folds over the board edges. Standard: 15-20 mm.
- Number of books
- Number of books to cut cloth for.
What each result means
- Cloth width (mm)
- Total width of bookcloth piece (board + spine + board + turn-ins + joints).
- Cloth height (mm)
- Total height of bookcloth piece (board height + turn-ins).
- Cloth width (inches)
- Cloth width in inches.
- Cloth height (inches)
- Cloth height in inches.
- Area per cover (cm²)
- Area of cloth needed for one book cover.
- Total area (sq in)
- Total cloth area for all books.
- Roll length needed (yards)
- Length from a standard 44-inch (112 cm) wide roll.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersBoard height (mm) = 216, Board width (mm) = 151, Spine width (mm) = 15, Turn-in allowance (mm) = 20 = 5 input(s) provided
- Calculate Cloth widthCloth width = turnInMm + boardWidthMm + jointGapMm + spineWidthMm + jointGapMm + boardWidth...371 = 371
- Calculate Cloth heightCloth height = turnInMm + boardHeightMm + turnInMm256 = 256
- Calculate Cloth widthCloth width = clothWidth / 25.414.61 = 14.61
- Calculate Cloth heightCloth height = clothHeight / 25.410.08 = 10.08
Engine last updated . Checked against 2 independently-derived tests — how we verify calculators. Built by Paul Gunder, a software engineer, not a licensed financial, medical, or legal professional.
Frequently Asked Questions
Why is the joint gap fixed at 7 mm instead of being an input I can adjust?
The calculator treats 7 mm as a sensible middle value within the standard 6–8 mm range binders use for a hinge that opens smoothly without straining or cracking the cloth. It's baked into the formula on both sides of the spine width rather than exposed as a control, so if your binding style calls for a noticeably wider or narrower joint, you'll need to adjust the cloth width output by hand.
Where do I get the spine width value this calculator asks for?
This tool doesn't compute spine width itself — it's a separate input you supply, ideally from a book block or spine-width calculator that accounts for page count, paper caliper, and sewing method. Plugging in a guessed spine width will throw off the cloth width formula, since spine width is added directly into cloth width = turn-in + board width + joint gap + spine width + joint gap + board width + turn-in.
How does the roll-length estimate handle multiple books?
It first figures out how many cover pieces fit side by side across a standard 112 cm (44 in) roll width, then divides your total book count by that number and rounds up to get the number of rows needed. Each row consumes one cloth-height's worth of roll length, so the total length in centimeters is rows × cloth height, converted to yards for ordering.
Why does increasing the turn-in allowance change both cloth width and cloth height?
Turn-in appears twice in each formula because it's added at both ends of every dimension: cloth width includes turn-in on the left and right edges, and cloth height includes turn-in on the top and bottom edges. Raising it from, say, 15 mm to 20 mm adds 10 mm total to both width and height (5 mm extra per side), not just 5 mm.
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