# Publishing Calc

Self-publishing arithmetic: page counts, reading and audiobook time, spine and cover size, trim sizes, royalties and ebook size.

## How to pay

Machine-payable over x402. USDC on: Base (eip155:8453), Solana (solana:5eykt4UsFv8P8NJdTREpY1vzqKqZKvdp), Polygon (eip155:137), Arbitrum One (eip155:42161).
No accounts. No API keys. No signup. The paying wallet is the account.

## Machine-readable

- OpenAPI: https://publishing-calc.x402tookit.com/openapi.json
- x402 manifest: https://publishing-calc.x402tookit.com/.well-known/x402
- Catalog (free): https://publishing-calc.x402tookit.com/catalog
- Health (free): https://publishing-calc.x402tookit.com/health
- Uptime (free): https://publishing-calc.x402tookit.com/uptime

## Endpoints (9)

### GET /audiobook-length — $0.02
Audiobook running time from a word count at about 9,300 words per hour (change it), as hours and clock time.
Params: words: number, wordsPerHour?: number
Example: https://publishing-calc.x402tookit.com/audiobook-length?words=80000

### GET /chapter-balance — $0.02
Split a total word count into N balanced chapters with exact per-chapter words, pages and reading minutes.
Params: totalWords: integer, chapters: integer, wordsPerPage?: number, wpm?: number
Example: https://publishing-calc.x402tookit.com/chapter-balance?totalWords=100003&chapters=3

### GET /cover-size — $0.02
Full paperback cover width and height with bleed from trim size and page count, in inches, mm and pixels.
Params: trimWidth: number, trimHeight: number, pages: integer, paper?: string, pageThicknessIn?: number, bleed?: number, unit?: string, dpi?: number
Example: https://publishing-calc.x402tookit.com/cover-size?trimWidth=6&trimHeight=9&pages=300&paper=white

### GET /ebook-size — $0.02
Estimate ebook file size in KB and MB from word count, image count and average image size (all adjustable).
Params: words: number, images?: integer, avgImageKb?: number, bytesPerWord?: number, textCompression?: number, overheadKb?: number
Example: https://publishing-calc.x402tookit.com/ebook-size?words=80000&images=10

### GET /page-count — $0.02
Pages from a word count at your words-per-page figure, rounded up, plus even page count and sheets for print.
Params: words: number, wordsPerPage?: number, frontBackPages?: number
Example: https://publishing-calc.x402tookit.com/page-count?words=80000&wordsPerPage=250

### GET /print-royalty — $0.02
Print book royalty per copy from list price, printing cost and royalty rate, plus break-even price and total.
Params: listPrice: number, printCost: number, royaltyRate: number, model?: string, copies?: number
Example: https://publishing-calc.x402tookit.com/print-royalty?listPrice=20&printCost=4&royaltyRate=60

### GET /reading-time — $0.02
Silent reading time for a word count at your words-per-minute (default 238), as minutes and hours:minutes:seconds.
Params: words: number, wpm?: number
Example: https://publishing-calc.x402tookit.com/reading-time?words=47600

### GET /spine-width — $0.02
Print book spine width in inches and mm from page count and paper type (white, cream, color) or your own thickness.
Params: pages: integer, paper?: string, pageThicknessIn?: number
Example: https://publishing-calc.x402tookit.com/spine-width?pages=300&paper=white

### GET /trim-sizes — $0.02
Standard US trade book trim sizes in inches and mm, or look up one size like 6x9 and its closest standard.
Params: size?: string
Example: https://publishing-calc.x402tookit.com/trim-sizes?size=6x9

## Terms

Self-publishing arithmetic computed locally from the numbers you give. Paper thickness, words per page and narration pace are common published figures that vary by printer, typeface and narrator: check your printer's own cover template and royalty calculator before ordering. Not legal, tax or financial advice.