Kokoro 82M vs OpenAI gpt-4o-mini-tts
Kokoro 82M is an open-weight text-to-speech model you can call on this endpoint; OpenAI gpt-4o-mini-tts is a closed model from OpenAI. Below: what each costs for three realistic workloads, the limits that apply, and when to choose which.
OpenAI figures are public list prices and documented limits, checked 2026-09-16 against the provider page. Inference APIs prices are read live from the price list.
- Cost: Kokoro 82M is cheaper in all three workloads, by 57%.
- Limits: OpenAI: Rate limits scale with usage tier. Here: no per-minute or per-day caps.
Side by side
| Kokoro 82M | OpenAI gpt-4o-mini-tts | |
|---|---|---|
| Served by | Inference APIs | OpenAI |
| Model author | Hexgrad | OpenAI |
| Model id | hexgrad/Kokoro-82M | gpt-4o-mini-tts |
| Price | $5.20 / 1M characters | $12.00 / 1M characters |
| Capabilities | Text to speech, 54 voices, MP3 / WAV, 8 languages | Text to speech, Instructable style |
| Weights | Open | Closed |
| Status | Available | Available |
| Limits | No per-minute or per-day request or token caps; usage draws on a prepaid balance | Rate limits scale with usage tier. |
| 300 characters → audio | 0.84 s | not measured by us |
What three workloads cost
List prices applied to the same work. The cheaper side of each row is in bold.
| Workload | Kokoro 82M | OpenAI gpt-4o-mini-tts | Difference |
|---|---|---|---|
| One 1,000-word article (about 6,000 characters) | $0.03 | $0.07 | 57% |
| One hour of narration (about 54,000 characters) | $0.28 | $0.65 | 57% |
| One million characters (about 18 hours of speech) | $5.20 | $12.00 | 57% |
Kokoro 82M is cheaper in all three workloads, by 57%.
When to choose which
- Cost is the deciding factor; it is cheaper in every workload above
- You want open weights: the same model can be moved to another host or self-hosted later
- Interactive speech: sub-second responses for a paragraph in our measurement
- You need voices in several languages at a low price per character
- You need to steer tone and delivery with natural-language instructions
Measured speed
Median of three runs on 2026-09-16: a 300-character paragraph to mp3, timed from request to last byte. Expect ±30% with time of day. We did not measure OpenAI and do not quote other people's numbers; read "not measured" as unknown, not slow. Method and raw numbers: speed measurements.
Switching from OpenAI
Both speak the OpenAI wire format. The edit is the base URL, the key and the model id; then re-run your own prompts, because it is a different model.
import os
from openai import OpenAI
# before: OpenAI
# client = OpenAI(base_url="https://api.openai.com/v1", api_key=os.environ["OPENAI_API_KEY"])
# MODEL = "gpt-4o-mini-tts"
# after: Inference APIs
client = OpenAI(base_url="https://api.inferenceapis.com/v1", api_key=os.environ["INFERENCE_API_KEY"])
MODEL = "hexgrad/Kokoro-82M"
resp = client.audio.speech.create(model=MODEL, voice="af_heart", input="Hello there")More detail, including Node, LangChain and LiteLLM: switching OpenAI-compatible providers.
FAQ
Which is cheaper, Kokoro 82M or OpenAI gpt-4o-mini-tts?
Kokoro 82M is cheaper in all three workloads, by 57%. The table above uses list prices: Kokoro 82M $5.20 / 1M characters; OpenAI gpt-4o-mini-tts $12.00 / 1M characters.
Can I switch from OpenAI gpt-4o-mini-tts to Kokoro 82M without rewriting code?
Yes, if you call it through an OpenAI-compatible client. Change the base URL to https://api.inferenceapis.com/v1, swap the API key, and set the model to hexgrad/Kokoro-82M. Because it is a different model, re-run your prompts and evaluations before moving production traffic.
What limits apply to OpenAI gpt-4o-mini-tts?
Rate limits scale with usage tier. On Inference APIs there are no per-minute or per-day request or token caps; usage draws on a prepaid balance.
Spotted a price or limit that has changed? Tell us and we will re-check the provider page.