A 5.25×8 book on KDP requires minimum margins of 0.375”–0.875” inside (depending on page count) and 0.25” outside, with fonts embedded and an even page count. The spine width is page count × 0.0025” (cream) or × 0.002252” (white). At this trim, an 80,000-word novel produces roughly 295 pages at $4.54 printing cost. The 5.25×8 is a practical middle ground — slightly wider than 5×8 with more breathing room for text, but still compact enough for genre fiction readers.
When to use 5.25×8 instead of 5×8
The 5.25” × 8” trim is 0.25” wider than the mass-market 5×8. That quarter-inch makes a real difference:
- More comfortable reading — an extra 0.25” of text width reduces the cramped feeling that 5×8 can have at smaller font sizes
- Slightly fewer pages — roughly 5-8% fewer pages than 5×8 for the same manuscript, which saves on printing costs
- Still genre-appropriate — readers won’t notice the difference from 5×8 when holding the book. It still feels like a genre paperback.
Choose 5.25×8 when:
- Your romance or thriller is 85K+ words and 5×8 would produce 350+ pages
- You want 11pt body text but 5×8 feels too tight at that size
- Your cover designer recommends slightly more spine real estate
Stick with 5×8 when genre convention matters most (especially romance series where readers expect consistent sizing).
Margin requirements
Minimum inside (gutter) margin
| Page Count | Minimum Inside Margin |
|---|---|
| 24–150 pages | 0.375” |
| 151–300 pages | 0.5” |
| 301–500 pages | 0.625” |
| 501–700 pages | 0.75” |
| 701–828 pages | 0.875” |
Minimum outside margins
| Edge | No bleed | With bleed |
|---|---|---|
| Outside | 0.25” | 0.375” |
| Top | 0.25” | 0.25” |
| Bottom | 0.25” | 0.25” |
Recommended margins
| Edge | Recommended |
|---|---|
| Inside (gutter) | 0.65”–0.8” |
| Outside | 0.5”–0.6” |
| Top | 0.6”–0.7” |
| Bottom | 0.65”–0.8” |
Check your page count and margin tier with the KDP Book Calculator.
Spine width
Cream paper: page count × 0.0025” White paper: page count × 0.002252”
| Pages | Cream Spine | White Spine |
|---|---|---|
| 200 | 0.500” | 0.450” |
| 250 | 0.625” | 0.563” |
| 295 | 0.738” | 0.664” |
| 300 | 0.750” | 0.676” |
| 350 | 0.875” | 0.788” |
Calculate yours with the Spine Width Calculator.
Page count and printing cost
| Word Count | Pages | Cost (B&W, cream) | vs 5×8 |
|---|---|---|---|
| 50,000 | ~210 | ~$3.52 | ~10 fewer pages |
| 60,000 | ~245 | ~$3.94 | ~15 fewer pages |
| 70,000 | ~275 | ~$4.30 | ~15 fewer pages |
| 80,000 | ~295 | ~$4.54 | ~15 fewer pages |
| 90,000 | ~335 | ~$5.02 | ~15 fewer pages |
The savings over 5×8 are modest per book — roughly $0.18–$0.24 per copy. But at scale (1,000+ copies/year), it adds up. And fewer pages means a slightly thinner book that’s easier to hold for extended reading.
Cambric applies the correct margins for 5.25×8 and every other KDP trim size. Pick your size, choose a template, export.
Get Cambric — $199
Cover dimensions
Cover width = 5.25” + spine + 5.25” + 0.25” = 10.75” + spine Cover height = 8” + 0.25” = 8.25”
Example: 295 pages on cream
- Spine: 0.738”
- Cover: 10.75” + 0.738” = 11.488” × 8.25”
- At 300 DPI: 3,446 × 2,475 pixels
Use the Cover Size Calculator for your exact dimensions.
PDF export settings
Same as all KDP trims:
- Page size: exactly 5.25” × 8” (378 × 576 points)
- Fonts: embedded
- Color: RGB, Grayscale, or CMYK
- Images: 300 DPI minimum
- Page count: even
- No printer marks
Related specifications
- 5×8 on KDP — the slightly smaller mass-market size
- 5.5×8.5 on KDP — the most popular fiction trim
- 5.25×8 on IngramSpark — IS version with PDF/X-1a
- KDP Book Calculator — page count, cost, royalty
- Trim sizes explained — full comparison of all trims