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Self-hosted speech-to-text cost calculator

Transcribing 1,000 hours of English audio a month as a batch job, Canary-Qwen 2.5B (5.63% WER on the Open ASR Leaderboard) on a Vast.ai RTX 4090 needs about 4.8 GPU-hours, $1.96 in rental, against $258 for Deepgram Nova-3 and $180 for OpenAI gpt-4o-mini-transcribe. The GPU price is a marketplace median. The speed is an estimate.

Enter your own audio hours below. The calculator picks an open model and a GPU, then compares that bill with OpenAI, Deepgram, AssemblyAI, Google, AWS, and hosted Whisper.

Audio hours per month
When it runs

Pay for the GPU hours the job runs.

Language

$1.96

this month · $0.002 per audio hour · or $295.24 if the GPU stays on

Canary-Qwen 2.5B

WER 5.63%

Vast.ai · NVIDIA GeForce RTX 4090
$0.4044/hr median · RTFx 207 per GPU, estimate · 4.8 GPU-hours

The pick is the lowest WER among setups whose bill is no more than twice the cheapest one, or $10 more, whichever is larger.

WER is the average word error rate on the Open ASR Leaderboard English short-form sets (AMI, Earnings-22, GigaSpeech, LibriSpeech, SPGISpeech, TED-LIUM, VoxPopuli). Lower is better.

Lowest bill$0.24

Parakeet TDT 0.6B v2, WER 6.05%
Vast.ai RTX 4090 24GB on-demand median

Measured speed$0.33

Parakeet TDT 0.6B v2 on Vast.ai A100 SXM4 80GB on-demand median. RTFx is the board’s A100 80GB SXM measurement.

Monthly cost at 1k audio hours

Self-host, this batch$1.96
Self-host, GPU left on$295.24
OpenAI mini$180.00
Deepgram$258.00
AssemblyAI$210.00
AWS Transcribe$360.00
Google STT$180.00
Groq turbo$40.00

Against the APIs

  • Groq turbo$40.00$0.04 per audio hour · Self-host costs less this month.
  • DeepInfra Voxtral$60.00$0.06 per audio hour · Self-host costs less this month.
  • Together Whisper$90.00$0.09 per audio hour · Self-host costs less this month.
  • Together Parakeet$90.00$0.09 per audio hour · Self-host costs less this month.
  • Groq v3$111.00$0.11 per audio hour · Self-host costs less this month.
  • AssemblyAI U-2$150.00$0.15 per audio hour · Self-host costs less this month.

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Speech-to-text deployment plan

1k audio hours · batch

Canary-Qwen 2.5BVast.ai · NVIDIA GeForce RTX 4090

$1.96 this month

Deepgram $258.00 for the same work. GPU rental only.

  1. Split long files into 30-second chunks with voice-activity detection before batching. Whisper-family models are trained on 30-second windows.
  2. Pin the model revision and the serving image tag, so a rebuild does not change the output.
  3. Run a sample of your own data through the model and the API you compare against, and score both.

Self-hosted Whisper vs Deepgram and OpenAI cost

At 1,000 audio hours a month in batch, Canary-Qwen 2.5B on a Vast.ai RTX 4090 is $1.96 of GPU rental. Deepgram Nova-3 is $258, OpenAI gpt-4o-mini-transcribe $180, and Amazon Transcribe $360. The cheapest hosted open model is Groq whisper-large-v3-turbo at $40.

The batch number assumes you only pay for GPU hours you use. Left on for all 730 hours, the same GPU is $295.24 a month. That is where most self-hosted speech projects lose money: a GPU sized for peak streaming traffic sits idle overnight. Both figures are GPU rental only, with no engineering, storage, or egress.

Best open-source speech-to-text models: WER vs cost

WER is the average word error rate on the Open ASR Leaderboard English short-form sets (AMI, Earnings-22, GigaSpeech, LibriSpeech, SPGISpeech, TED-LIUM, VoxPopuli). Lower is better. Every score links to the leaderboard. Pick a model to see every GPU and provider for it.

Open speech-to-text models on rented GPUs for 1k audio hours a month: Open ASR Leaderboard WER, RTFx, hourly price, and monthly bill. Checked November 1, 2026.
ModelWERLanguagesGPUProvider$/hourAlways-on / monthThis workloadPer audio hourRTFx per GPU
Parakeet TDT 0.6B v2
CC-BY-4.0
6.05%EnglishNVIDIA GeForce RTX 4090Vast.ai
RTX 4090 24GB on-demand median
$0.4044 median$295.24$0.24$0.00021,674 estimate
Parakeet TDT 0.6B v3
CC-BY-4.0
6.32%25 European languagesNVIDIA GeForce RTX 4090Vast.ai
RTX 4090 24GB on-demand median
$0.4044 median$295.24$0.25$0.00021,648 estimate
Canary 1B Flash
CC-BY-4.0
6.35%English, German, Spanish, FrenchNVIDIA GeForce RTX 4090Vast.ai
RTX 4090 24GB on-demand median
$0.4044 median$295.24$0.78$0.0008517 estimate
Canary-Qwen 2.5B · recommended
CC-BY-4.0
5.63%EnglishNVIDIA GeForce RTX 4090Vast.ai
RTX 4090 24GB on-demand median
$0.4044 median$295.24$1.96$0.002207 estimate
Qwen3-ASR 1.7B
Apache-2.0
5.76%Not in the card metadataNVIDIA GeForce RTX 4090Vast.ai
RTX 4090 24GB on-demand median
$0.4044 median$295.24$5.53$0.005573 estimate
Granite Speech 3.3 8B
Apache-2.0
5.74%English, French, German, Spanish, PortugueseNVIDIA GeForce RTX 4090Vast.ai
RTX 4090 24GB on-demand median
$0.4044 median$295.24$5.63$0.005672 estimate
Whisper large-v3
Apache-2.0
7.44%99 languagesNVIDIA GeForce RTX 4090Vast.ai
RTX 4090 24GB on-demand median
$0.4044 median$295.24$5.62$0.005672 estimate
Whisper large-v3-turbo
MIT
7.83%99 languagesNVIDIA GeForce RTX 4090Vast.ai
RTX 4090 24GB on-demand median
$0.4044 median$295.24$4.09$0.004199 estimate
Distil-Whisper large-v3.5
MIT
7.21%EnglishNVIDIA GeForce RTX 4090Vast.ai
RTX 4090 24GB on-demand median
$0.4044 median$295.24$4.05$0.004100 estimate
Voxtral Mini 3B
Apache-2.0
7.05%8 languages in the cardNVIDIA GeForce RTX 4090Vast.ai
RTX 4090 24GB on-demand median
$0.4044 median$295.24$7.45$0.007454 estimate
Voxtral Small 24B
Apache-2.0
6.62%8 languages in the cardNVIDIA GeForce RTX 4090 × 4Vast.ai
RTX 4090 24GB on-demand median
$1.6178 median$1,181$15.13$0.015127 estimate

faster-whisper (CTranslate2) is a runtime for the Whisper weights, not a separate model. It has no row on the leaderboard, so it gets no WER or RTFx of its own here. Expect the Whisper large-v3 accuracy and a different speed. “Measured” means the board’s A100 80GB SXM figure. Every other GPU is a bandwidth estimate.

Speech-to-text API pricing per minute, with WER

List prices checked November 1, 2026. A dash in WER means that API has no row on the Open ASR Leaderboard table used here. A dash in a price means that API has no such mode.

Managed and hosted speech-to-text API prices per audio minute, the monthly bill for 1k hours, and leaderboard WER. Checked November 1, 2026.
APITypeBatch $/minReal-time $/minThis monthPer audio hourWER
OpenAI gpt-4o-mini-transcribeManaged API$0.003—$180.00$0.18—
OpenAI gpt-transcribeManaged API$0.0045—$270.00$0.27—
OpenAI gpt-realtime-whisperManaged API—$0.017———
Deepgram Nova-3 (monolingual)Managed API$0.0043$0.0077$258.00$0.26—
AssemblyAI Universal-3.5 Pro / 3.6 Pro RealtimeManaged API$0.0035$0.0075$210.00$0.216.21%
AssemblyAI Universal-2 / Universal-StreamingManaged API$0.0025$0.0025$150.00$0.15—
Amazon TranscribeManaged API$0.006$0.01$360.00$0.36—
Google Cloud STT v2Managed API$0.003tiered$180.00$0.186.63%
Groq whisper-large-v3-turboHosted open model$0.00067—$40.00$0.047.83%
Groq whisper-large-v3Hosted open model$0.00185—$111.00$0.117.44%
Together Whisper large-v3Hosted open model$0.0015$0.0035$90.00$0.097.44%
Together Parakeet TDT 0.6B v3Hosted open model$0.0015—$90.00$0.096.32%
DeepInfra Voxtral MiniHosted open model$0.001—$60.00$0.067.05%

AssemblyAI’s 6.21% is the board row universal-3-pro, and Google’s 6.63% is chirp_3. Hosted open models show the WER of the open weights they serve.

Speech-to-text GPU cost per hour and per month, by provider

On-demand hourly price and the always-on month (hourly × 730). Community and non-preemptible rates are shown only where that provider publishes them. Each price links to the provider’s pricing page, checked November 1, 2026. A dash means that provider does not list this GPU.

GPU price per hour and per 730-hour month, by provider. Checked November 1, 2026.
GPURunPodLambdaModalVast.aiAWSGoogle Cloud
L4
L4
$0.59/hr On-demand
$430.70/mo
Community $0.44/hr · $321.20/mo
checked November 1, 2026
—
Nvidia L4
$0.7992/hr Preemptible
$583.42/mo
Non-preemptible $2.3976/hr · $1,750/mo
checked November 1, 2026
L4 on-demand median
$0.3378/hr On-demand median
$246.58/mo
checked November 1, 2026
g6.xlarge
$0.8048/hr On-demand
$587.50/mo
checked November 1, 2026
g2-standard-4
$0.7068/hr On-demand
$515.99/mo
checked November 1, 2026
A10 / A10G—
1× A10
$1.29/hr On-demand
$941.70/mo
checked November 1, 2026
Nvidia A10
$1.1016/hr Preemptible
$804.17/mo
Non-preemptible $3.3048/hr · $2,413/mo
checked November 1, 2026
A10 on-demand median
$0.2453/hr On-demand median
$179.09/mo
checked November 1, 2026
g5.xlarge
$1.006/hr On-demand
$734.38/mo
checked November 1, 2026
—
RTX 4090
RTX 4090
$0.89/hr On-demand
$649.70/mo
Community $0.34/hr · $248.20/mo
checked November 1, 2026
——
RTX 4090 24GB on-demand median
$0.4044/hr On-demand median
$295.24/mo
checked November 1, 2026
——
A100
A100 SXM 80GB
$1.79/hr On-demand
$1,307/mo
Community $1.39/hr · $1,015/mo
checked November 1, 2026
A100 PCIe 80GB
$1.79/hr On-demand
$1,307/mo
Community $1.19/hr · $868.70/mo
checked November 1, 2026
1× A100 SXM 40GB
$1.99/hr On-demand
$1,453/mo
checked November 1, 2026
Nvidia A100 80GB
$2.4984/hr Preemptible
$1,824/mo
Non-preemptible $7.4952/hr · $5,471/mo
checked November 1, 2026
A100 SXM4 80GB on-demand median
$1.1253/hr On-demand median
$821.49/mo
checked November 1, 2026
p4de.24xlarge
$27.45/hr On-demand · 8 GPUs
$20,036/mo
checked November 1, 2026
a2-ultragpu-1g
$5.0688/hr On-demand
$3,700/mo
checked November 1, 2026
H100
H100 SXM
$3.99/hr On-demand
$2,913/mo
Community $2.69/hr · $1,964/mo
checked November 1, 2026
H100 PCIe
$2.89/hr On-demand
$2,110/mo
Community $1.99/hr · $1,453/mo
checked November 1, 2026
1× H100 SXM
$4.29/hr On-demand
$3,132/mo
checked November 1, 2026
1× H100 PCIe
$3.29/hr On-demand
$2,402/mo
checked November 1, 2026
Nvidia H100 SXM5
$3.9492/hr Preemptible
$2,883/mo
Non-preemptible $11.85/hr · $8,649/mo
checked November 1, 2026
H100 SXM on-demand median
$2.2044/hr On-demand median
$1,609/mo
checked November 1, 2026
H100 PCIe on-demand median
$2.5422/hr On-demand median
$1,856/mo
checked November 1, 2026
p5.4xlarge
$6.88/hr On-demand
$5,022/mo
checked November 1, 2026
a3-highgpu-8g
$88.49/hr On-demand · 8 GPUs
$64,598/mo
checked November 1, 2026

How the self-hosted speech-to-text cost is calculated

Prices checked November 1, 2026. A month is 730 hours. The bill is GPU rental only. WER is the average word error rate on the Open ASR Leaderboard English short-form sets (AMI, Earnings-22, GigaSpeech, LibriSpeech, SPGISpeech, TED-LIUM, VoxPopuli). Lower is better. The pick is the lowest WER among setups whose bill is no more than twice the cheapest one, or $10 more, whichever is larger.

Sources, RTFx scaling, and what was left out

RTFx is audio seconds transcribed per second of GPU time. The board measured it on one A100-SXM4-80GB at batch size 64. Other GPUs use that RTFx × (the GPU's NVIDIA memory bandwidth ÷ 2,039 GB/s), and are marked estimates. A model that needs more than one GPU is assumed to scale linearly with the GPU count. A 24 GB card may not hold batch 64 for the larger models, so its scaled rate can run high. RTFx is a batch number. A streaming server that holds latency down serves fewer streams than RTFx, so the real-time GPU count here is a floor.

Benchmark

Models

  • Parakeet TDT 0.6B v2 (NVIDIA, 0.6B, CC-BY-4.0): WER 6.05%, RTFx 3,386.02 on A100 80GB SXM. Languages: English.
  • Parakeet TDT 0.6B v3 (NVIDIA, 0.6B, CC-BY-4.0): WER 6.32%, RTFx 3,332.74 on A100 80GB SXM. Languages: 25 European languages.
  • Canary 1B Flash (NVIDIA, 1B, CC-BY-4.0): WER 6.35%, RTFx 1,045.75 on A100 80GB SXM. Languages: English, German, Spanish, French.
  • Canary-Qwen 2.5B (NVIDIA, 2.5B, CC-BY-4.0): WER 5.63%, RTFx 418.28 on A100 80GB SXM. Languages: English.
  • Qwen3-ASR 1.7B (Alibaba Qwen, 1.7B, Apache-2.0): WER 5.76%, RTFx 147.93 on A100 80GB SXM. Languages: Not in the card metadata.
  • Granite Speech 3.3 8B (IBM, 9B, Apache-2.0): WER 5.74%, RTFx 145.42 on A100 80GB SXM. Languages: English, French, German, Spanish, Portuguese.
  • Whisper large-v3 (OpenAI, 2B, Apache-2.0): WER 7.44%, RTFx 145.51 on A100 80GB SXM. Languages: 99 languages.
  • Whisper large-v3-turbo (OpenAI, 0.8B, MIT): WER 7.83%, RTFx 200.19 on A100 80GB SXM. Languages: 99 languages.
  • Distil-Whisper large-v3.5 (Hugging Face, 0.8B, MIT): WER 7.21%, RTFx 202.03 on A100 80GB SXM. Languages: English.
  • Voxtral Mini 3B (Mistral, 5B, Apache-2.0): WER 7.05%, RTFx 109.86 on A100 80GB SXM. Languages: 8 languages in the card.
  • Voxtral Small 24B (Mistral, 24B, Apache-2.0): WER 6.62%, RTFx 54.09 on A100 80GB SXM. Languages: 8 languages in the card.

API prices checked November 1, 2026

GPU prices and bandwidth

Left out

  • Diarization, timestamps, and language detection add-ons. API add-on prices are not in the bill.
  • Volume and committed-use discounts, and spot or preemptible prices on AWS and Google Cloud.
  • Free tiers and signup credits.

Deployment checklist

  1. Split long files into 30-second chunks with voice-activity detection before batching. Whisper-family models are trained on 30-second windows.
  2. Pin the model revision and the serving image tag, so a rebuild does not change the output.
  3. Run a sample of your own data through the model and the API you compare against, and score both.
  4. Measure your own throughput on the GPU you rent before you budget the month. The rate here is a starting point.
  5. Put a queue in front of the GPU and retry failed jobs, so a preempted or restarted instance does not drop work.
  6. If you need diarization or timestamps, price them separately. WER and RTFx here are plain transcription.

Related tools: the self-hosted OCR cost calculator, the embedding cost calculator, and the open-source LLM hosting cost calculator. Related reading: LLM API pricing, LLM cost optimization, and AI agent development.

Self-hosted speech-to-text cost: questions

Is self-hosting Whisper cheaper than the OpenAI API?

Usually, for batch audio. OpenAI gpt-4o-mini-transcribe is $0.003 a minute, $0.18 per audio hour. The leaderboard measured Whisper large-v3 at an RTFx of 145.5 on one A100 80GB SXM, so an hour of audio takes under 25 seconds of that GPU. Even at RunPod's $1.79 an hour that is about $0.01 of GPU time per audio hour. The catch is utilization: a GPU you leave on all month costs the same whether you send it audio or not.

Which open-source speech-to-text model is the most accurate?

On the Open ASR Leaderboard English short-form table (commit of 22 May 2026), the lowest average WER among the open models here is NVIDIA Canary-Qwen 2.5B at 5.63, then Granite Speech 3.3 8B at 5.74 and Qwen3-ASR 1.7B at 5.76. Whisper large-v3 is 7.44. These are English scores. Check the per-language results before using any of them for other languages.

What does RTFx mean?

Inverse real-time factor: seconds of audio transcribed per second of compute. An RTFx of 3,386, which the board reports for Parakeet TDT 0.6B v2, means one GPU-second transcribes about 56 minutes of audio. The board measured RTFx on one A100-SXM4-80GB at batch size 64. On other GPUs this page scales it by memory bandwidth and labels the result an estimate.

Why do Deepgram, AWS, and OpenAI show no WER?

They have no row on the Open ASR Leaderboard table used here. The page shows a dash instead of borrowing a number from a vendor's own benchmark. AssemblyAI and Google do have board rows, but under model names that are not exactly the SKU on the price page, and the table says which row was used.

How many GPUs do I need for real-time transcription?

This calculator divides your peak concurrent streams by the batch RTFx of the setup and rounds up, with at least one GPU on all month. That is a floor. A streaming server that keeps latency low runs smaller batches than the benchmark, so it serves fewer streams per GPU. Load-test your own server with your stream count before you size it.

Is faster-whisper on the leaderboard?

Not as its own row. faster-whisper is a CTranslate2 runtime for the Whisper weights, so its accuracy is the Whisper large-v3 accuracy and its speed depends on the GPU, batch size, and quantization. This page does not give it a separate RTFx.