Benchmark / AI Transcription
The most accurate AI transcription tools, actually tested.
We run the same reference audio through each tool and measure the word error rate. Lower error, higher accuracy. Ranked best first.
Every "best AI transcription tool" list ranks the same tools in the same order, usually straight from the marketing copy. We do it differently. We run the same reference audio through each tool and measure the actual word error rate, the percentage of words it gets wrong. The ranking on this page is a measurement, not an opinion.
Below is every major AI transcription tool we track, with the price pulled from its live pricing page and, where we have tested it, the accuracy we measured ourselves. The tools split into two camps: developer APIs you call from code, like AssemblyAI and Deepgram, and finished apps you use in a browser, like Otter, Fireflies and Descript. We cover both.
AssemblyAI
API de speech-to-text pra devs.
Full results
2 tested · 9 tracked| Rank | Tool | Accuracy (tested) | From | Free | |
|---|---|---|---|---|---|
| 01 | AssemblyAI API de speech-to-text pra devs. | 96.9% | $0.15/hr | Yes | Visit |
| 02 | Deepgram API de transcrição de baixa latência. | 95.6% | — | Yes | Visit |
| · | Descript Edição de áudio/vídeo baseada em transcrição. | Not tested yet | $24/mo | Yes | Visit |
| · | Fireflies.ai Assistente de reunião que grava e transcreve. | Not tested yet | $18/mo | Yes | Visit |
| · | Happy Scribe Transcrição e legendagem. | Not tested yet | $17/mo | — | Visit |
| · | OpenAI Whisper API API de speech-to-text da OpenAI (whisper-1). | Not tested yet | — | — | Visit |
| · | Otter.ai Meeting notes e transcrição em tempo real. | Not tested yet | $16.99/mo | Yes | Visit |
| · | Rev Transcrição por IA e humana. | Not tested yet | $29.99/mo | Yes | Visit |
| · | Sonix Transcrição automatizada multi-idioma. | Not tested yet | $10/hr | — | Visit |
Method: accuracy = 1 minus word error rate, averaged over our reference audio set. Prices are the cheapest paid tier we track and may change. Tools without a score are in our catalog with testing in progress. Some links are affiliate links.
Popular comparisons
How we measure
Accuracy here means word error rate, or WER. We take an audio clip with a known, human-verified transcript, run it through the tool, and count how many words it substituted, dropped or added. A WER of 3% means 97% of the words were correct. We report accuracy as 1 minus WER, so higher is always better.
Our current reference set uses standardized read-speech clips (the Harvard sentences) at telephone quality. We are expanding it with accented speech, background noise and multi-speaker meetings, because the tool that wins on clean audio is not always the one that wins on a noisy call. Prices come from each tool's live pricing page: subscription apps show the cheapest paid monthly tier, and usage-based APIs show the per-hour rate.
Frequently asked
What is the most accurate AI transcription tool?+
In our reference test, AssemblyAI scored highest at 96.9% word accuracy, narrowly ahead of Deepgram at 95.6%. On clean audio the gap is small. The differences grow on harder audio like accents and background noise, which we are adding to the benchmark now.
Is there a free AI transcription tool?+
Yes. Deepgram, Otter, Fireflies, Descript and Rev all offer a free tier or free credits. The developer APIs are especially generous to start: Deepgram includes 200 dollars in free credits, enough to transcribe many hours before you pay anything.
How much does AI transcription cost?+
It depends on the model. Usage-based APIs are the cheapest per unit: AssemblyAI runs about 0.15 dollars per hour of audio. Subscription apps start around 17 to 30 dollars per month (Happy Scribe 17, Otter 16.99, Fireflies 18, Rev 29.99), usually with a monthly minute allowance.
Should I use a transcription API or an app?+
Use an app such as Otter, Fireflies or Descript if you want to upload a file or record a meeting and read the transcript in a browser, with no code. Use an API such as AssemblyAI or Deepgram if you are a developer building transcription into your own product and want to pay only for what you process.
How do you measure accuracy?+
We use word error rate against a known reference transcript, the same method used in academic speech research. It is fully reproducible: same audio, same reference text, same score every time. It is the number no listicle publishes, because producing it takes real engineering.