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Spine text checker

Find out if your spine can carry text, and the largest type size that fits with the printer's clearance.

Printer
Your spine text (optional, stays on this device)
% of size

Our starting estimate. Capital letters are shorter than the type size; enter your font's own cap height if you know it.

Spine textAllowed
Spine width
0.500 in
Width for text
0.375 in
Largest size, capitals
38.5 pt
Largest size, lowercase too
27 pt

KDP prints spine text from 80 pages, with 0.0625 in clear on each side of the text. Type sizes are our estimate.

    Spine foldsClearance and end marginsTo scale: the spine turned on its side
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    Short answer

    KDP prints spine text only on books with more than 79 pages, and wants 0.0625 in clear on each side of it. A 200 page book on cream paper has a 0.5 in spine, leaving 0.375 in for text: about 38.5 pt in capitals or 27.0 pt with lowercase.

    How to use it

    1. Choose the printer and enter your page count. The word count to pages tool gives you one if the book isn't laid out yet.
    2. Pick the paper and trim size. For IngramSpark, paste the spine width from its calculator.
    3. Read whether spine text is allowed and how much width is left after the clearances.
    4. Type your title and author to see them on the spine at the largest size that fits.
    5. Take the numbers to the cover calculator and build the full cover template.

    How it works

    Spine width comes from the page count. The printer keeps a strip clear along each fold, and the text has to fit in what is left.

    KDP spine width = page count x paper thickness (0.0025 in a page for cream)
    Width for text = spine width - 2 x clearance
    Largest size (lowercase) = width for text x 72 pt
    Largest size (capitals) = width for text x 72 pt / cap height

    Worked example: a 200 page KDP paperback on cream paper. 200 x 0.0025 in = 0.5 in spine. Take 0.0625 in off each side: 0.5 in - 0.125 in = 0.375 in. That is 27.0 pt for a line with lowercase, and 27.0 pt / 0.7 = 38.5 pt for capitals. The same book at 79 pages is too thin for spine text.

    The type sizes are our estimate for one line of text, not a printer rule. Real fonts differ, so check the final file at full size and leave some air.

    Reference

    KDP paperback spines, with 0.0625 in clearance each side. Sizes are our estimate at a 70% cap height.

    PagesCream spineCapitalsLowercaseWhite spineCapitals
    800.2 in7.7 pt5.4 pt0.1802 in5.6 pt
    1000.25 in12.8 pt9.0 pt0.2252 in10.3 pt
    1500.375 in25.7 pt18.0 pt0.3378 in21.8 pt
    2000.5 in38.5 pt27.0 pt0.4504 in33.4 pt
    3000.75 in64.2 pt45.0 pt0.6756 in56.6 pt
    4001 in90.0 pt63.0 pt0.9008 in79.7 pt
    6001.5 in141.4 pt99.0 pt1.3512 in126.1 pt

    Questions authors ask

    How many pages do you need for spine text on KDP?

    KDP says it only prints spine text on books with more than 79 pages, so 80 is the minimum. At 79 pages or fewer, keep the spine plain: a small shift in binding would push the text onto the front or back cover.

    How much space do I leave around spine text?

    KDP wants at least 0.0625 in between the text and each spine edge. IngramSpark wants 0.0625 in on spines 0.35 in and wider and 0.0313 in on narrower ones. Lulu wants 0.125 in on each side.

    What font size should spine text be?

    As large as fits. The tool takes the spine width, subtracts the clearance on both sides and converts what is left to points (72 points to the inch). That is our estimate for a single line. KDP asks for cover text of at least 7 pt, so a spine that cannot hold 7 pt type is better left plain.

    Why are capitals allowed bigger than lowercase?

    Capital letters fill only part of the type size, a share called the cap height. Our default of 70% is an estimate, not a measurement of your font. Lowercase text with letters like g, p and y needs the whole size, so it has to be smaller. Enter your font's own cap height for a closer figure.

    Can I put text on an 80 page spine?

    KDP allows it, but there is very little room. On cream paper 80 pages make a 0.2 in spine and leave 0.075 in for text: about 7.7 pt in capitals and 5.4 pt with lowercase, under KDP's 7 pt minimum. Many authors leave it plain until the book is longer.

    How many pages do IngramSpark and Lulu need for spine text?

    IngramSpark: no spine text on perfect bound books under 48 pages. Lulu: none on books of 80 pages or fewer. IngramSpark does not publish its spine formula, so paste the width from its calculator.

    Does my title have to be on the spine?

    No. KDP's metadata rules say a print book's title must be on the cover, on the spine or the front cover. A thin book with a plain spine is fine as long as the front cover carries the title.

    Before and after this step

    Related tools

    Sources

    Last verified against each printer's official help pages. Type sizes are our own estimate from the space left. Printers change their specs, so check the source before you order a proof.

    KDP

    IngramSpark

    Lulu