Lulu Spine Width Calculator
Spine width for Lulu paperbacks and hardcovers, straight from Lulu's published formula and table.
Lulu paperback spine width chart
| Pages | Spine (in) | Spine (mm) |
|---|---|---|
| 32 | 0.132 | 3.4 |
| 50 | 0.173 | 4.4 |
| 80 | 0.240 | 6.1 |
| 100 | 0.285 | 7.2 |
| 150 | 0.398 | 10.1 |
| 200 | 0.510 | 13.0 |
| 250 | 0.623 | 15.8 |
| 300 | 0.736 | 18.7 |
| 400 | 0.961 | 24.4 |
| 500 | 1.186 | 30.1 |
| 600 | 1.411 | 35.8 |
| 700 | 1.637 | 41.6 |
| 800 | 1.862 | 47.3 |
Lulu hardcover spine width table
| Pages | Spine (in) | Spine (mm) |
|---|---|---|
| 24–84 | 0.25 | 6 |
| 85–140 | 0.5 | 13 |
| 141–168 | 0.625 | 16 |
| 169–194 | 0.688 | 17 |
| 195–222 | 0.75 | 19 |
| 223–250 | 0.813 | 21 |
| 251–278 | 0.875 | 22 |
| 279–306 | 0.938 | 24 |
| 307–334 | 1 | 25 |
| 335–360 | 1.063 | 27 |
| 361–388 | 1.125 | 29 |
| 389–416 | 1.188 | 30 |
| 417–444 | 1.25 | 32 |
| 445–472 | 1.313 | 33 |
| 473–500 | 1.375 | 35 |
| 501–528 | 1.438 | 37 |
| 529–556 | 1.5 | 38 |
| 557–582 | 1.563 | 40 |
| 583–610 | 1.625 | 41 |
| 611–638 | 1.688 | 43 |
| 639–666 | 1.75 | 44 |
| 667–694 | 1.813 | 46 |
| 695–722 | 1.875 | 48 |
| 723–750 | 1.938 | 49 |
| 751–778 | 2 | 51 |
| 779–799 | 2.063 | 52 |
| 800 | 2.125 | 54 |
Specs last checked against Lulu's published specs in September 2026.
Frequently asked questions
How does Lulu calculate paperback spine width?
Spine width in inches = (interior pages ÷ 444) + 0.06. In millimetres it is (pages ÷ 17.48) + 1.524. A 300-page paperback has a 0.736 in spine.
How does Lulu calculate hardcover spine width?
Lulu hardcovers (casewrap and linen with dust jacket) use a fixed table instead of a formula. For example, 24–84 pages get a 0.25 in spine and 417–444 pages get 1.25 in.
What is the minimum page count at Lulu?
Paperbacks need at least 32 interior pages and hardcovers at least 24. Coil bound and saddle stitch books have no spine.