Leaf & Spine

5.25 x 8 in · 400 pages

400-page 5.25 x 8 in book: spine width & cover size

A 400-page 5.25 x 8 in paperback has a spine of 0.9008 in (22.88 mm) on white paper or 1 in on cream. Full cover with bleed: 11.651 x 8.25 in.

0.901 inSpine, white paper22.88 mm
1 inSpine, cream paper25.4 mm
11.65 x 8.25Full cover, inchesincl. bleed
421 gEstimated weight14.9 oz

Cover template (white paper)

Barcode areaBACK COVER5.25 x 8 inFRONT COVER5.25 x 8 inSPINE 0.901 inFull cover 11.651 x 8.25 in incl. 0.125 in bleed
Red: bleed (trimmed off) · dashed: 0.25 in safe zone · shaded: spine. Download a full-size template from the calculator.

Spine and cover by paper type

PaperSpineSpine (mm)Full cover (in)Full cover (mm)At 300 ppi
White paper, black ink0.9008 in22.88 mm11.651 x 8.25 in295.9 x 209.6 mm3,495 x 2,475 px
Cream paper, black ink1 in25.4 mm11.75 x 8.25 in298.5 x 209.6 mm3,525 x 2,475 px
Standard color (white)0.9008 in22.88 mm11.651 x 8.25 in295.9 x 209.6 mm3,495 x 2,475 px
Premium color (white)0.9388 in23.85 mm11.689 x 8.25 in296.9 x 209.6 mm3,507 x 2,475 px

Per-page factors are those published by KDP; IngramSpark and offset printers use their own paper calipers.

Other printers: spine by paper PPI

Paper PPITypical stockSpineSpine (mm)
350 PPIBulky / heavy stock (~70 lb text)1.1429 in29.03 mm
400 PPICream book paper (~55 lb)1 in25.4 mm
444 PPIWhite book paper (~50 lb)0.9009 in22.88 mm
500 PPILightweight text (~45 lb)0.8 in20.32 mm
600 PPIThin text (~40 lb)0.6667 in16.93 mm

If your printer quotes pages per inch (PPI), spine = pages ÷ PPI. Ask for the exact PPI of your chosen stock.

Designing this cover

  • Build the cover canvas at 11.651 x 8.25 in — or 3,495 x 2,475 px at 300 ppi.
  • The back cover runs from the left edge to 5.375 in; the spine from 5.375 to 6.276 in; the front cover after that.
  • Spine text is allowed — centre it and keep 0.0625 in clear on each side.
  • Keep titles and faces at least 0.25 in inside the trim; KDP places the barcode in a 2 x 1.2 in area at the lower right of the back cover.
  • Export as a flattened PDF (PDF/X-1a is safest) with fonts embedded.

Nearby page counts

PagesSpine (white)Spine (cream)Full cover (white)
340 pages0.7657 in0.85 in11.516 x 8.25 in
350 pages0.7882 in0.875 in11.538 x 8.25 in
360 pages0.8107 in0.9 in11.561 x 8.25 in
370 pages0.8332 in0.925 in11.583 x 8.25 in
380 pages0.8558 in0.95 in11.606 x 8.25 in
390 pages0.8783 in0.975 in11.628 x 8.25 in
410 pages0.9233 in1.025 in11.673 x 8.25 in
420 pages0.9458 in1.05 in11.696 x 8.25 in
430 pages0.9684 in1.075 in11.718 x 8.25 in
440 pages0.9909 in1.1 in11.741 x 8.25 in
450 pages1.0134 in1.125 in11.763 x 8.25 in
460 pages1.0359 in1.15 in11.786 x 8.25 in

400 pages in other trim sizes

TrimSpine (white)Full cover (white)
5 x 8 in0.9008 in11.151 x 8.25 in
5.06 x 7.81 in0.9008 in11.271 x 8.06 in
5.5 x 8.5 in0.9008 in12.151 x 8.75 in
6 x 9 in0.9008 in13.151 x 9.25 in
6.14 x 9.21 in0.9008 in13.431 x 9.46 in
6.69 x 9.61 in0.9008 in14.531 x 9.86 in
7 x 10 in0.9008 in15.151 x 10.25 in
7.5 x 9.25 in0.9008 in16.151 x 9.5 in
8 x 10 in0.9008 in17.151 x 10.25 in
8.5 x 8.5 in0.9008 in18.151 x 8.75 in
8.5 x 11 in0.9008 in18.151 x 11.25 in

Spine width depends only on page count and paper; the cover width changes with the trim.

Frequently asked questions

How wide is the spine of a 400-page 5.25 x 8 in book?
On white paper it is 0.9008 in (22.88 mm); on cream paper 1 in (25.4 mm), using KDP's per-page factors.
What size should the full cover be?
For white paper: 11.651 x 8.25 in (295.9 x 209.6 mm) including 0.125 in bleed on every side. For cream paper: 11.75 x 8.25 in.
Can I put text on the spine?
Yes. KDP allows spine text only for books with more than 79 pages; keep it at least 0.0625 in (1.6 mm) from each spine edge.
How heavy is a 400-page 5.25 x 8 in paperback?
About 421 g (14.9 oz) on white paper with a standard cover — useful for estimating postage.