Inworld STT-1 vs GPT-4o Mini Transcribe
Inworld STT-1 is ahead of GPT-4o Mini Transcribe on final-text delay. The Pipecat Dataset and The Ocular Dataset are too close to call.
Last updated Methodology by Dileep Chagam
Accuracy vs speed
Each dot is one model. Bottom-left is best: fewer errors and a faster final transcript.
Which to pick
Inworld STT-1 is the better pick over GPT-4o Mini Transcribe on every measure that separates them: quick turn-taking once the caller stops (589ms sooner). For accuracy on clean, scripted audio and accuracy on real phone conversations, the gap is inside the margin of error, so neither is ahead.
The four metrics, side by side
- Inworld STT-1
- 2.72%10th
- GPT-4o Mini Transcribe
- 3.35%11th
Too close to call: inside the margin of error
- Inworld STT-1
- 10.60%16th
- GPT-4o Mini Transcribe
- 4.45%12th
Too close to call: inside the margin of error
- Inworld STT-1
- 1.06s6th
- GPT-4o Mini Transcribe
- No text until the speaker stops
Not comparable
- Inworld STT-1
- 41ms2nd
- GPT-4o Mini Transcribe
- 630ms16th
Inworld STT-1, 589ms sooner
Lower is better on every metric. The small figure is each model's place in the whole field. What each metric measures.
- WER · Word error rate
- Share of words the model got wrong: replaced, missing or added. Lower is better.
- Pipecat Dataset
- 1,000 short public clips from Pipecat's STT benchmark dataset.
- Ocular Dataset
- 8 recordings from 4 real phone conversations, licensed from Ocular.
- TTFT · Time to first text
- How long after the audio starts streaming until the first words appear.
- TTFS · Final-text delay
- How long after the caller stops until the full transcript arrives. A voice agent waits for this before it replies.
First text and final text, at three percentiles
Inworld STT-1 shows first text after 1.07s and final text after 65ms, and GPT-4o Mini Transcribe shows first text after 40.84s and final text after 1.53s, on a bad turn (P95) across the same streamed turns.
| Measure | Model | P50 | P90 | P95 |
|---|---|---|---|---|
| Time to first text | Inworld STT-1 | 1.06s | 1.07s | 1.07s |
| GPT-4o Mini Transcribe | No text until the speaker stops | |||
| Final-text delay | Inworld STT-1 | 41ms | 60ms | 65ms |
| GPT-4o Mini Transcribe | 630ms | 1.34s | 1.53s | |
- P50 / P90 / P95 · Typical, slow and slowest turns
- Half of turns are faster than P50. Only 1 in 10 is slower than P90, and 1 in 20 slower than P95.
How each ranks among all 17 models
Place among the 17 models on each metric. Lower is better on all four.
| Metric | STT-1 | 4o Mini Transcribe |
|---|---|---|
| Pipecat Dataset WER | 2.72%10th of 17 | 3.35%11th of 17 |
| Ocular Dataset WER | 10.60%16th of 17 | 4.45%12th of 17 |
| Time to first text | 1.06s6th of 15 | Not comparable |
| Final-text delay | 41ms2nd of 17 | 630ms16th of 17 |
How much audio each model was tested on
| Model | Pipecat clips | Ocular recordings | Turns timed | Failed |
|---|---|---|---|---|
| Inworld STT-1 | 1,000 | 8 | 206 | 0 |
| GPT-4o Mini Transcribe | 1,000 | 8 | 206 | 0 |
Only clips with usable text count, so the two totals can differ. How WER is scored.
Related comparisons
- Inworld STT-1 vs Soniox STT-RT v5
- Inworld STT-1 vs Speechmatics Linden
- Inworld STT-1 vs Cartesia Ink 2
- Inworld STT-1 vs GPT Realtime Whisper
- Inworld STT-1 vs Reson8
- Inworld STT-1 vs Google Chirp 3
- Inworld STT-1 vs Deepgram Nova-3
- Inworld STT-1 vs Smallest Pulse
- Inworld STT-1 vs AssemblyAI Universal 3.6 Pro
- Inworld STT-1 vs GPT-4o Transcribe
- Inworld STT-1 vs Deepgram Flux English
- Inworld STT-1 vs Deepgram Flux Multilingual
- Inworld STT-1 vs Gradium
- GPT-4o Mini Transcribe vs Deepgram Nova-3
- GPT-4o Mini Transcribe vs Smallest Pulse
- GPT-4o Mini Transcribe vs GPT-4o Transcribe
- GPT-4o Mini Transcribe vs Deepgram Flux English
- GPT-4o Mini Transcribe vs Soniox STT-RT v5
- GPT-4o Mini Transcribe vs Speechmatics Linden
- GPT-4o Mini Transcribe vs Cartesia Ink 2
- GPT-4o Mini Transcribe vs GPT Realtime Whisper
- GPT-4o Mini Transcribe vs Reson8
- GPT-4o Mini Transcribe vs Google Chirp 3
- GPT-4o Mini Transcribe vs AssemblyAI Universal 3.6 Pro
- GPT-4o Mini Transcribe vs Deepgram Flux Multilingual
- GPT-4o Mini Transcribe vs Gradium
Frequently asked questions
Which is more accurate, Inworld STT-1 or GPT-4o Mini Transcribe?
Inworld STT-1 and GPT-4o Mini Transcribe are too close to call on accuracy. On the 1,000 public Pipecat clips, Inworld STT-1 scores 2.72% and GPT-4o Mini Transcribe 3.35%, with likely ranges of 1.67 to 4.68% and 3.08 to 3.65%. The ranges overlap, so the difference is too close to call. On the eight licensed Ocular recordings, Inworld STT-1 scores 10.60% and GPT-4o Mini Transcribe 4.45%, with likely ranges of 3.85 to 22.76% and 3.22 to 5.55%. The ranges overlap, so the difference is too close to call. Word error rate counts incorrect, missing, and extra words, so lower is better.
Is Inworld STT-1 faster than GPT-4o Mini Transcribe?
Yes. Inworld STT-1 finishes the transcript 589ms sooner. Inworld STT-1 has the final transcript 41ms after the speaker stops and GPT-4o Mini Transcribe 630ms, at the median. Both are measured on the same 206 streamed turns.
Is Inworld STT-1 or GPT-4o Mini Transcribe better for voice agents?
Inworld STT-1 finishes the transcript 589ms sooner, and the two are too close to call on real conversations. A voice agent cannot reply until the final transcript arrives, and the Ocular recordings are real conversations.
Do Inworld STT-1 and GPT-4o Mini Transcribe stream text while the speaker is talking?
Only Inworld STT-1. GPT-4o Mini Transcribe returns no text until the speaker stops, which matters if your agent reacts to partial transcripts.