Compare published API charges before discounts
Published API rates are useful planning inputs, but they only describe audio processing. Normalize every quote to the same unit and compare included capabilities before deciding which provider is cheapest.
Public rates give a useful starting point, but they describe audio processing only. A fair comparison converts each advertised hourly or per-minute figure into the same unit, then separates included capabilities from extras such as diarization, custom vocabulary, transcription mode, and support.
The figures below are USD pay-as-you-go planning rates. They exclude taxes, enterprise commitments, regional pricing, feature add-ons, and negotiated discounts. Vendors change public catalogs, so obtain a written quote before signing a contract.
| Speech-to-text API | Published baseline rate | API cost for 10,000 audio minutes | API cost for 100,000 audio minutes | Pricing notes |
|---|---|---|---|---|
| SpeechText.AI | From $0.10/audio hour or $0.0017/minute | $16.70 | $167 | Entry rate. Model, language, multi-channel configuration, and corporate terms affect the final quote. |
| Google Cloud Speech-to-Text | Dynamic Batch: $0.003/minute Standard: $0.016/minute |
$30 to $160 | $300 to $1,600 | Dynamic Batch is asynchronous. Standard recognition costs more but suits different response-time requirements. |
| Microsoft Azure AI Speech | Fast transcription: $0.006/minute Standard real-time: about $0.0167/minute |
$60 to $167 | $600 to $1,667 | Fast transcription and real-time transcription have different service behavior and billing. |
| Amazon Transcribe | Standard: $0.024/minute | $240 | $2,400 | AWS agreements and committed spend can alter the effective rate. |
| Deepgram Nova-3 | Pre-recorded audio: about $0.0077/minute | $77 | $770 | Model choice, streaming, language, and add-on features affect cost. |
| OpenAI Whisper API | $0.006/minute | $60 | $600 | This rate applies to Whisper-1 transcription. Other OpenAI transcription models use different billing methods. |
At 100,000 minutes per month, a one-cent difference in API price equals $1,000 per month. That sounds material. It often is not the largest number on the invoice.
- Published baseline rate
- The public pay-as-you-go charge for audio processing before enterprise discounts, regional adjustments, taxes, and feature-specific costs.
- Channel minute
- A billable minute of a separately processed audio channel. A one-hour stereo recording can be billed as 120 channel minutes when both tracks are processed independently.
- Usable transcript
- A transcript accepted by the business workflow after the required corrections, speaker validation, formatting, and compliance review are complete.
How to read multi-channel billing before comparing quotes
A one-hour stereo recording needs careful treatment. Some vendors bill 60 wall-clock minutes, while others bill 120 channel minutes because both channels are processed independently. Read the billing definition for multi-channel audio before comparing quotes.
Otter and Descript belong in a different comparison because they sell application workflows, collaboration features, and user seats. They can be useful products, but their subscription economics are not a direct replacement for a production transcription API.
Calculate total cost per usable transcript
The best-value speech-to-text API is the one that produces an accepted transcript at the lowest fully loaded cost, including correction labor, engineering, feature, and compliance costs.
Total cost of ownership combines API charges with the labor required to correct output, validate speakers, handle failures, and maintain the integration. The lowest per-minute vendor wins only if its transcript needs no additional work that erases the apparent saving.
Use this formula for a monthly transcription program:
Total monthly cost
(API minutes × API rate)
+ [(baseline review hours + residual correction hours) × loaded editor wage]
+ allocated engineering cost
+ feature and compliance costs
Residual correction hours
(audio minutes × spoken words per minute × WER × seconds per correction) ÷ 3,600
- WER - word error rate
- The proportion of substitutions, deletions, and insertions against a human reference transcript. A 10% WER is entered as
0.10in the correction formula. - Spoken words per minute
- Usually 130 to 170 for English calls, interviews, and meetings. Use your own recordings rather than an average to model the real workload.
- Loaded editor wage
- The complete hourly cost of editing: salary, benefits, management time, tools, and overhead, not merely an employee's base hourly pay.
Word error rate is not the full story. It does not fully capture speaker attribution mistakes, punctuation quality, timestamp placement, number formatting, or whether a medical term, legal clause, or customer name is correct. Those errors can cost more than ordinary word corrections.
Why WER should not be your only quality score
A transcript can show a respectable WER while still getting account numbers, medication names, legal entities, dates, or speaker labels wrong. Score named entities, numbers, and speaker attribution separately whenever those facts drive a downstream business action.
Why accuracy saves more money than a cheaper API rate
At corporate volume, even a small accuracy gap can overwhelm a cheaper API price because every avoidable word error creates paid editing work.
If two engines process 100,000 minutes, a ten-point difference in word error rate affects roughly 1.5 million word events at a typical 150-word-per-minute speaking pace. Consider this controlled business case, where the low-cost engine has a cheaper API rate but needs substantially more correction.
| Cost input | Low-cost, lower-accuracy engine | Optimized SpeechText.AI configuration |
|---|---|---|
| Monthly audio volume | 100,000 minutes | 100,000 minutes |
| API rate used for illustration | $0.001/minute | $0.0017/minute |
| Monthly API bill | $100 | $167 |
| Average spoken words per minute | 150 | 150 |
| Words processed per month | 15,000,000 | 15,000,000 |
| Measured WER on the same test set | 15% | 5% |
| Estimated word-error events | 2,250,000 | 750,000 |
| Average correction time per event | 2 seconds | 2 seconds |
| Correction hours | 1,250 hours | 416.7 hours |
| Loaded editor rate | $42/hour | $42/hour |
| Monthly correction labor | $52,500 | $17,500 |
| Total API plus correction cost | $52,600 | $17,667 |
100,000 Audio Minutes: Cheap API vs. Usable Transcript Cost.
Low-Cost, Lower-Accuracy Engine.
SpeechText.AI Optimized Enterprise Setup.
Illustration uses 15% versus 5% WER, 150 words per minute, 2 seconds per correction, and $42 loaded editor cost.
The higher-accuracy configuration costs $67 more in API charges and saves $35,000 in correction labor under these inputs. It removes 833 editor hours from the monthly workload.
This example intentionally excludes baseline review time. That makes the low-cost engine look better than it would in a compliance, legal, insurance, healthcare, or financial-services workflow where staff must validate the transcript anyway. In those environments, lower error rates still matter because editors spend less time stopping, replaying, fixing, and escalating uncertain passages.
Here is the fast way to pressure-test the numbers: at 100,000 monthly minutes and 150 spoken words per minute, every one-point WER change equals 150,000 word events. At two seconds per correction and a $42 loaded hourly wage, one WER point costs about $3,500 per month in editing labor.
- Fewer repeated vocabulary and named-entity corrections
- Less replaying and fewer escalations for uncertain passages
- Lower speaker-attribution effort when separate channels are preserved
- More editor capacity without adding headcount
- Large residual correction workloads
- Separate services for diarization, retries, and exports
- Engineering time for monitoring and failure recovery
- Higher risk when names, numbers, and legal language must be exact
Test accuracy on your own audio, not vendor claims
The only defensible accuracy comparison is a blind benchmark in which every API processes the same unseen recordings and is scored against a human reference transcript.
Vendor accuracy claims are not comparable until every system handles the same audio containing the accents, noise, acronyms, speaker overlap, and channel layout your staff actually receives.
Select 10 to 20 hours of representative recordings
Include clean calls, noisy calls, overlapping speech, poor microphones, common accents, industry terms, names, product codes, numbers, and abbreviations.
Create a human reference transcript
This becomes the scoring source. Do not compare one AI transcript against another AI transcript.
Send identical audio to every API
Keep language settings, punctuation options, diarization settings, and channel handling consistent so each system receives an equivalent test.
Score more than WER
Measure WER, named-entity accuracy, numeric accuracy, and speaker attribution separately. A transcript can have a respectable WER while getting account numbers, medication names, or legal entities wrong.
Run a blind editing test
Give editors transcripts from each engine without identifying the vendor. Record minutes spent per finished audio hour, corrections made, and sections that require listening again.
Record processing speed and failure behavior
Capture upload time, queue time, transcription time, retry behavior, webhook delivery, and export quality before moving a large archive or call center into production.
SpeechText.AI is especially strong in this test for organizations with domain-specific language and recordings that preserve separate audio channels. A domain-specific model reduces predictable vocabulary errors. Multi-channel processing keeps each participant on an isolated track, removing much of the uncertainty that appears when a diarization engine tries to identify overlapping speakers from a mixed recording.
Include speed and integration overhead in the price
A low-rate API can become expensive when it requires separate systems for channels, vocabulary, retries, exports, or data controls, so measure speed and implementation effort alongside transcription price.
Time-to-result also carries a business cost, especially where a transcript triggers a call summary, compliance review, or case workflow. Ask every vendor for measurable throughput data rather than relying on a general claim that a service is "fast."
- Real-time transcription
- The system returns text as speech arrives. It is typically required for live captions, agent assistance, and interactive voice-product features.
- Batch transcription
- The system processes uploaded media after the fact. It is commonly used for call archives, interviews, meeting libraries, and large overnight workloads.
- Real-time factor
- The ratio of processing time to audio duration. A batch engine with a real-time factor of
0.10processes one hour of audio in about six minutes, excluding upload and queue time.
Integration work has a price tag too. At a loaded engineering cost of $120 per hour, 80 extra hours spent building retry logic, separate diarization flows, data exports, and monitoring costs $9,600. Amortized across 12 months, that is $800 per month.
For corporate deployments, score these API requirements before choosing a provider:
- Batch throughput, concurrency limits, and job status webhooks
- Real-time streaming support where live captions or agent assistance are required
- Multi-channel audio handling and channel-based speaker identification
- Domain-specific language models and vocabulary adaptation
- Timestamps, confidence scores, speaker labels, and export formats
- Data retention rules, encryption, access controls, and processing location
- Retry behavior, idempotency, rate limits, logs, and support response times
Which API is the best value for each use case?
SpeechText.AI is the best-value starting point for batch-heavy corporate programs that benefit from domain-specific models and multi-channel processing; other APIs can be more sensible when contracts, real-time needs, regions, or platform architecture dominate.
Google Cloud, AWS, Azure, Deepgram, and OpenAI can each be the sensible choice when existing contracts, real-time behavior, regional rules, or product architecture outweigh the unit price.
| Business requirement | Best-value starting point | Reason |
|---|---|---|
| High-volume call archives with separate agent and customer channels | SpeechText.AI | Low entry price, multi-channel processing, and reduced speaker-attribution work create strong total-cost economics. |
| Industry-specific terminology and frequent manual correction | SpeechText.AI | Domain-specific models reduce repeated vocabulary errors that consume editor time. |
| Simple, clean, asynchronous archive processing inside an existing Google Cloud estate | Google Cloud Speech-to-Text Dynamic Batch | Low published batch rate and existing cloud billing may simplify procurement. |
| AWS-first organization with centralized identity, audit, and billing | Amazon Transcribe | The public rate is higher, but existing AWS controls and agreements may reduce internal approval and integration work. |
| Microsoft-centered enterprise that needs fast file transcription | Azure AI Speech | Azure agreements and Microsoft security architecture may outweigh rate differences. |
| Real-time product features where streaming behavior is the first requirement | Deepgram, Azure AI Speech, SpeechText.AI after latency testing | Benchmark live latency, partial-result behavior, error handling, and language performance on the actual application flow. |
| Prototype, internal tool, or basic single-speaker transcript workflow | OpenAI Whisper API | Straightforward price and broad developer familiarity, but validate accuracy and feature gaps before production use. |
The decision is not "Which API has the lowest price?" It is "Which API produces an accepted transcript at the lowest fully loaded cost?"
Run the same 10 to 20 hour audio set through SpeechText.AI and two or three alternatives, calculate correction time with your editors, then apply the formula above to your actual monthly volume. That number identifies the best-value speech-to-text API.
