InkAlign Suite

Publishing tools for KDP authors

A focused set of utilities for trim, spine, and print-ready PDFs — the same rigor you expect from pro layout software, without the learning curve.

  • KDP Interior Auto-Fixer

    Normalize 6×9 interiors with KDP bleed, mirror margins, and gutter tiers. Health scan, watermarked preview, and print-ready export after checkout.

    Open Tool

  • Spine Width Calculator

    White vs cream paper thickness factors — instant spine estimate in inches for cover design, with one-click copy for your template.

    Open Tool

  • Cover validation

    Upload your KDP wrap PDF — we measure it with pdf-lib and compare to spine + trim + bleed. Download a blank template at the exact size.

    Open Tool
  • Coming Soon

    CMYK Color Verifier

    Spot RGB-only assets and out-of-gamut risks before you upload — built for KDP print color expectations.

  • Coming Soon

    Barcode Generator

    ISBN-13 barcode blocks sized for KDP cover templates — placement guides and safe margins included.

Tool

Spine width calculator

Quick estimate for a paperback spine before you design your cover. For the exact value, use Amazon's KDP cover template after you set trim and paper.

Estimated Spine Width: 0.4504 in

Formula: page count × paper thickness per page. Estimate only — confirm with KDP's cover template before printing.

Tool

Cover validation

Check your paperback wrap PDF against KDP-style dimensions: width = 2 × trim width + spine + 0.25″ bleed, height = trim height + 0.25″ bleed. Spine uses white (0.002252″/page) or cream (0.0025″/page). Always confirm in KDP before publishing.

Blank template

One empty page at the exact target width × height (white).

Single Fix from $9.99 unlocks the full interior pipeline. More tools ship here first — no bloat, just what authors actually print.