10,000-character TTS script: one 48-cent job or three chunks?

A 10,000-character script costs 48 cents on Sume TTS if you send it as one job. The rate is $0.0475 per 1,000 characters, so 10,000 characters is $0.475, and each job is rounded up to the next whole cent. One job fits well under the 20,000-character request limit, so you do not need to split it to fit.

The arithmetic

Sume's per-character book is the provider list price per character times 1.25, rounded up to cents per job. The catalog lists 38 millionths of a dollar per character at list, which becomes 47.5 millionths at the public rate. Spaces and punctuation count as characters.

Why the chunk count barely matters

Rounding up is per job, so each extra job can add up to one cent. Three chunks happened to land on the same total here, but five and ten chunks cost two cents more. The real cost of chunking is not money. Separate jobs are separate takes, so the delivery can differ slightly between them, and you now have files to join.

When splitting is still right

Split when a single job would pass 20,000 characters, since the request is rejected beyond that. Split when you want to regenerate one section without paying for the rest: a 2,000-character retake costs 10 cents, a full 10,000-character retake costs 48. Split along sentence boundaries, not mid-sentence, so each chunk ends cleanly. The post on how Sume splits a script into sentence ids shows where those boundaries fall.

• Under 20,000 characters and no section you expect to redo: one job.
• Over 20,000 characters: split on a sentence boundary, never mid-sentence.
• Expecting edits: chunk by section so a retake is a small bill.

Check before you send

Count characters the way the API does, including spaces, and run a cost-only preview if you use the MCP tool. The one-job-versus-per-sentence rounding gap is covered in the cent rounding post linked below.

A worked example

Say a 10,000-character narration has five sections of about 2,000 characters. As one job it is 48 cents. Suppose the client asks for a rewrite of section three. Re-running the whole script costs another 48 cents and may change delivery in sections that were already approved. Re-running only section three costs 10 cents, assuming you kept the sections as separate jobs from the start.

That is the real decision. If revisions are likely, plan for chunks and accept the extra cent or two of rounding. If the script is final and short enough, one job is simpler: one file, one voice take, no joins. Keep each script's text and the job result so you can recreate a take later.