Endpaper Calculator
Endsheet dimensions from book block size and attachment method.
About this calculator
Endpapers (endsheets) are the folded sheets glued or sewn at the front and back of a book that anchor the text block to the cover boards — one leaf pastes down to the board, the other hangs free as the fly-leaf. This calculator sizes the flat, unfolded sheet you need to cut: width comes out to twice the book block's width plus a fixed 5mm hinge allowance (since the sheet folds in half at the spine, with a little extra room for the hinge to flex), while height simply matches the block height. It supports three attachment methods that share the same sheet dimensions but differ in sheet count: a simple tipped-on fold and a sewn-in version each use one sheet per endpaper, while the multi-section fine-binding style uses two — a plain waste sheet plus a decorative sheet — layered together.
Every book needs two endpapers (front and back), so total sheets is sheets-per-endpaper × 2 × number of books, and the calculator sums total area in cm² to help budget decorative paper purchases. It also flags whether your sheet size fits within standard A4 or A3 stock, which matters if you're buying pre-cut paper rather than a full sheet you'll trim yourself. One thing to check separately: this calculator doesn't verify paper grain direction, which for endpapers should run parallel to the spine fold just as it does for text pages — use the paper grain direction calculator alongside this one to confirm you're cutting from the right orientation.
Inputs
Results
Sheet width (mm)
301
Sheet height (mm)
210
How to Use This Calculator
- Enter the text block height and width in millimeters.
- Select the endpaper type: simple fold (tipped on), sewn in, or multi-section for fine binding.
- Enter the number of books to calculate total endpaper sheets needed.
- Read the sheet width and height in mm (and inches) — these are the cut dimensions for each endpaper sheet.
- Note that the sheet width is approximately twice the block width plus a hinge allowance for folding.
- Use the total area in cm² to estimate how much decorative or coordinating paper to purchase.
How the result changes with Book block width (mm)
| Book block width (mm) | Sheet width (mm) | Sheet height (mm) |
|---|---|---|
| 74 | 153 | 210 |
| 111 | 227 | 210 |
| 222 | 449 | 210 |
| 370 | 745 | 210 |
What each input means
- Book block height (mm)
- Height of the text block in mm.
- Book block width (mm)
- Width of the text block in mm.
- Endpaper type
- 1 = Simple fold (tipped on), 2 = Sewn in, 3 = Multi-section (fine binding).
- Number of books
- Number of books to prepare endpapers for.
What each result means
- Sheet width (mm)
- Width of each endpaper sheet before folding (2× block width + hinge).
- Sheet height (mm)
- Height of each endpaper sheet (equals block height).
- Sheet width (inches)
- Sheet width in inches.
- Sheet height (inches)
- Sheet height in inches.
- Sheets per book
- Number of endpaper sheets needed per book.
- Total sheets needed
- Total endpaper sheets for all books.
- Total area (cm²)
- Total paper area needed for purchasing.
How this is calculated
Worked example, using the default values
- Identify Input Parameters4 parametersBook block height (mm) = 210, Book block width (mm) = 148, Endpaper type = 1, Number of books = 1 = 4 input(s) provided
- Calculate Sheet widthSheet width = 2 * blockWidthMm + hingeAllowanceMm301 = 301
- Calculate Sheet height210 = 210
- Calculate Sheet widthSheet width = sheetWidth / 25.411.85 = 11.85
- Calculate Sheet heightSheet height = sheetHeight / 25.48.27 = 8.27
Engine last updated . Checked against 3 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 endpaper sheet width roughly double the book's width instead of matching it?
An endpaper is one sheet folded in half at the spine to create two leaves — the paste-down (glued to the board) and the free fly-leaf. Because it's cut flat before folding, the unfolded sheet needs enough width to become both leaves after the fold, so the calculator doubles block width and adds a fixed 5mm hinge allowance so the fold can flex without cracking.
When would I need the multi-section endpaper option instead of a simple fold?
Multi-section (fine-binding) endpapers use two layered sheets per endpaper — a plain waste sheet plus a decorative sheet — rather than the single sheet a simple fold or sewn-in endpaper uses. This doubles your sheet count (and paper cost) but is standard for fine binding, where you want a decorative paper on display without that paper bearing the structural sewing or pasting stress directly.
What does the A3/A4 fit check actually verify?
It compares your calculated flat sheet dimensions (width and height, before folding) against standard A3 (420×297mm) and A4 (297×210mm) stock sizes to tell you whether you can cut your endpaper from a standard pre-cut sheet or need to buy larger stock and trim it down yourself — useful if you're sourcing decorative paper that only comes in standard sizes.
Why does the calculator recommend checking grain direction separately?
This calculator only computes flat dimensions and sheet count — it doesn't take a grain-direction input at all. Endpaper grain should run parallel to the spine fold, the same as text-block pages, so cutting from the wrong grain orientation would make the fold crack and resist lying flat no matter how correctly this calculator's dimensions were followed.
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