A weekly bedtime story: 52 narrations at 5,000 characters
A 5,000-character story each week for a year is 260,000 characters: $5.72 on MAI-Voice-2.1, $3.90 on Flash, $12.48 on Sume as 52 jobs.
A bedtime story of 5,000 characters narrated each week for 52 weeks is 260,000 characters, which costs $5.72 on MAI-Voice-2.1, $3.90 on Flash and $12.48 on Sume TTS as 52 jobs.
At about 15 characters per second (a planning assumption, not a Sume figure), a 5,000-character story is five to six minutes of audio, a comfortable size for one job.
The arithmetic
Rates come from Microsoft's launch page for the two MAI voices and from Sume's public TTS rate. The Sume rate is the list-price arithmetic ($0.0475 per 1,000 characters); the live figure for your workspace is in GET /v1/catalog, and a platform fee can apply on top of list arithmetic on your invoice.
| Option | Rate | Arithmetic | Cost |
|---|---|---|---|
| MAI-Voice-2.1 | $22 per 1M characters | 260,000 x $22 / 1,000,000 | $5.72 |
| MAI-Voice-2.1-Flash | $15 per 1M characters | 260,000 x $15 / 1,000,000 | $3.90 |
| Sume TTS 1.0, 52 separate jobs | $0.0475 per 1,000 characters, rounded up to the cent per job | 52 x ceil(5000 x $0.0000475 = $0.238 to the cent) = 52 x $0.24 | $12.48 |
| Sume TTS 1.0, packed into 13 jobs | same rate, at most 20,000 characters per request | 260,000 characters in 13 requests | $12.35 |
A calm voice, set once
Pick one voice and keep it; pace is set with the speed multiplier, which accepts 0.6 to 1.5, so 0.85 slows the read for sleepy listeners without changing the price.
At 5,000 characters a story is 24 cents on Sume (5,000 x $0.0000475 = $0.2375, rounded up), which is why the year is $12.48 as separate jobs.
- Volume accepts 0.5 to 2.0 if you need to match a music bed.
- An emotion guide is an optional generation_config field; it changes delivery, not price.
What Sume does and does not offer here
Sume does not list MAI-Voice-2.1 or MAI-Voice-2.1-Flash, so the first two rows are a price reference, not something you can call through Sume. Sume TTS 1.0 is a managed voice or avatar surface at POST /v1/tts-1.0/generate, and the TTS Router lists Sonic model ids only. A request takes up to 20,000 characters; synthesized audio over 1,200 seconds fails with tts_duration_exceeded and no credit is captured. Microsoft states the Flash model generates up to 45 seconds of audio per call, which matters for long reads.
- Long scripts: split on paragraph boundaries so each request stays at or under 20,000 characters and each audio file under 1,200 seconds.
- Output defaults to mp3 at 44,100 Hz and 128 kbps; ask for wav (pcm_s16le, 44,100) when the file feeds a render or a lip-sync step.
- Speed is a multiplier from 0.6 to 1.5 and volume from 0.5 to 2.0 in generation_config; they do not change the per-character price.
Submitting it on Sume
Paid MCP tools need an idempotency_key, and a cost-only dry run is available before you spend. Use the voice or avatar you already have, set language for any non-English text, and keep one key per item so a retry never bills twice. The tool names are tts_create for synthesis and tts_source_get for the accepted-script manifest.
Treat the table as list arithmetic. Re-check the live rate in the catalog before a large batch, because Microsoft's MAI pricing is a launch announcement dated 2026-10-01 and Sume rates are read from the repository price book as of 2026-10-08.
Sources
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Written by Sume