Publishing.
Professional tools for self-publishers, authors, and book designers. From royalty estimates to precise spine measurements — all synced to 2025 KDP standards.
The Profit Lab
Instantly estimate your KDP earnings. Enter list price, page count, and interior type to get your net royalty — accounting for marketplace fees and printing costs. Synced to 2025 rates.
The Book Spine Expert
Calculate your exact spine width to 4 decimal places. Uses KDP's official PPI constants for white (0.00225") and cream (0.0025") paper. Essential for designing print-ready covers.
Cover Dimension Calculator
Get your complete cover file dimensions — back + spine + front + bleed. Select trim size, page count, and paper type. Output in both inches and millimetres with a visual layout diagram.
Trim Size Registry
Reference guide to industry-standard paperback and hardcover trim dimensions. Includes Fiction (5×8), Trade (6×9), and Workbook (8.5×11) formats with KDP bleed and margin specs.