Cartesia Ink STT hours per plan vs Sume STT $0.60 per hour

Cartesia includes Ink speech-to-text hours in its monthly plans: about 1 hour 51 minutes on Free, 9 hours 16 minutes on Pro ($5), 115 hours 44 minutes on Startup ($49) and 740 hours 44 minutes on Scale ($299). Dividing price by hours gives roughly $0.54, $0.42 and $0.40 per hour. Sume STT 1.0 is $0.01 per audio minute, or $0.60 per hour, with no plan.

Plan figures

Hours and concurrency are quoted from Cartesia's page. The derived rate is plan price divided by included hours, and it only applies if you actually use all included hours.

Sume STT in the same terms

A Sume STT job takes a public HTTPS audio_url, optional language_code and duration_seconds from 1 to 600, then returns text and words[]. There is no plan: you pay $0.01 per audio minute for what you run, so unused capacity costs nothing.

import os, requests

r = requests.post(
    "https://api.sume.com/v1/stt-1.0/transcribe",
    headers={"Authorization": f"Bearer {os.environ['SUME_API_KEY']}",
             "Idempotency-Key": "stt-demo-001"},
    json={"audio_url": "https://example.com/call.mp3",
          "language_code": "en",
          "duration_seconds": 300},
)
print(r.status_code, r.json())

Reading the trade-off

At steady high volume, a Cartesia plan used fully is cheaper per hour. At low or spiky volume, an unused plan hour is wasted spend, and pay-per-minute can come out lower overall. Compute your own monthly hours before choosing.

Worked example

Here is the same exercise for transcription.

• Need 100 hours a month: Startup's about 115h 44m covers it at $49.
• Need 10 hours: Pro's about 9h 16m falls just short.
• At Sume's $0.01 per minute, 10 hours is $6.00, and 100 hours is $60.00.

Checklist before you commit

Cartesia's per-hour figure is only reached if you use the whole plan. Pay-per-minute has no such threshold.

• Check concurrency (Startup lists 20 STT requests).
• Check latency needs, since Cartesia also targets live use.
• Compare accuracy on your own audio.