Cost to make an audiobook with AI narration

The cost to make an audiobook with AI narration is mostly the text: every character of the manuscript times the text to speech rate. On Sume that rate is $0.0475 per 1,000 characters, plus a 5.5% agent fee by default, so a 500,000-character book joined into 25 chapter files comes to $24.00 before the fee.

The rates are read from the code behind API pricing. Request limits come from the TTS schema in the Sume API reference (the OpenAPI document behind the API reference docs) and the joining step from Timeline audio, read on 2026-09-29. This post is the budget; Text to speech for long text and audiobooks has the split-and-join steps.

How much does AI audiobook narration cost by book length?

Use your word processor's character count with spaces, because spaces and punctuation count. The manuscript sizes below are examples, and the totals assume one joined file per chapter across 25 chapters, which adds $0.25.

What adds to the cost?

• Retakes. A chapter you re-voice is billed again for its characters, so proof the text before you synthesize it.
• Chunk count. One request takes up to 20,000 characters, and the audio it returns must not exceed 1,200 seconds; longer fails with tts_duration_exceeded and captures no credit. Measure your first chunk's duration_seconds and size the rest from it.
• Joining. A Timeline audio concat joins up to 20 parts into one file of up to 1,800 seconds at $0.01 per job. A chapter longer than 30 minutes becomes more than one file.
• No per-voice or per-minute line: the /pricing/api rate card has one Text to speech row, priced per character.

Can the book be read in my own voice?

Yes, if you clone it first. Cloning happens in the Sume app (Assets → Voices, from an upload or a recording); there is no API route for it. You then send the clone's voi_ id as voice.id on every request, and speech in it bills at the same per-character rate. AI voiceover with my own voice covers the cloning step.

Can I sell an AI-narrated audiobook?

That depends on your tool's terms and on the store's rules, so check your distributor's own requirements for AI narration and file formats before you upload. Sume's terms say paid plans include commercial use as described on the pricing page, and require permission for any voice you submit, such as a clone of someone else's voice. Text to speech commercial use quotes the clauses.