How is voice API cost usually billed?

Speech-to-text is almost always billed per minute of audio. Text-to-speech is billed per character or per minute of generated speech depending on the provider. This tool normalises everything to a per-minute basis for easy comparison.

Why is ElevenLabs more expensive than OpenAI for TTS?

ElevenLabs prices premium, highly natural and clonable voices at a higher rate, while OpenAI's TTS targets a lower price point. The right choice depends on whether voice quality or cost matters more for your use case.

Do the premium tiers really cost more?

Yes. Premium STT models (higher accuracy, diarization) and premium TTS voices typically cost noticeably more per minute than standard tiers. The tool applies a multiplier so you can see the gap.

Is my data sent anywhere?

No. The calculator runs entirely in your browser. Nothing you enter is uploaded, stored or logged.

Voice API Cost Calculator

Compare voice API costs across providers

Adding speech to an app means paying for text-to-speech (TTS), speech-to-text (STT), or both — and prices vary widely between OpenAI, ElevenLabs, Google and Deepgram. This calculator takes your minutes of audio per day, a direction, and a quality tier, and shows the daily and monthly cost for each provider so you can choose on real numbers instead of marketing pages.

How it works

Costs are normalised to a per-minute rate. STT providers already bill per minute of input audio. For TTS, character-based pricing is converted using an average of roughly 150 spoken words (about 900 characters) per minute. The daily cost is then:

daily_cost = minutes_per_day × per_minute_rate × tier_multiplier

When you select “both”, the tool sums the TTS and STT rates for each provider. Premium tiers apply a multiplier to reflect higher-accuracy STT models and more natural TTS voices.

Tips for managing voice spend

Cache repeated TTS. Greetings, menu prompts and canned responses should be synthesised once and stored, not regenerated on every call.
Match the tier to the task. Use premium voices for customer-facing audio and standard tiers for internal transcription where accuracy tolerance is higher.
Trim silence before STT. Voice-activity detection removes dead air so you are not billed for minutes of silence.
Batch transcription. Offline batch STT is frequently cheaper than real-time streaming for recordings that do not need an instant transcript.