The Cloud Text-to-Speech API is priced monthly based on the amount of characters to synthesize into audio sent to the service.
|Feature||Monthly free tier||Paid usage|
|Standard (non-WaveNet) voices||0 to 4 million characters||$4.00 USD / 1 million characters|
|WaveNet voices||0 to 1 million characters||$16.00 USD / 1 million characters|
Google Cloud Platform costs
If you use other Google Cloud Platform resources in tandem with the Text-to-Speech API, such as Google App Engine instances, then you will also be billed for the use of those services. See the Google Cloud Platform Pricing Calculator to determine other costs based on current rates.