### Answer Yes, you can link an externally purchased toll-free number to Retell AI using Elastic SIP Trunking. [(1) ]() Here's how it works: 1. Set up Elastic SIP Trunking with your telephony provider - Configure termination (for outbound calls) with the termination SIP URI from your provider - Configure origination (for inbound calls) by pointing to Retell's SIP server:

sip:sip.retellai.com

2. Move your toll-free number to the SIP trunk [(2) ]() - Assign your toll-free number to the elastic SIP trunk in your telephony provider's dashboard 3. Import the number into Retell - Provide the termination SIP URI you configured - If using credential-based authentication, supply the username and password - You can import via the dashboard or programmatically using the [Import Number API]() Once imported, the toll-free number will work like any Retell-purchased number—it will appear in your dashboard and you can make/receive calls with it. Retell supports providers like Twilio, Telnyx, and Vonage, and other providers that support SIP trunks can also be used. [(1) ]()

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.

​ To learn more, see the sources I considered: [[1] Custom Telephony Overview](https://docs.retellai.com/deploy/custom-telephony) [[2] Twilio](https://docs.retellai.com/deploy/twilio) ​

### Answer Yes, when you purchase a toll-free number directly from Retell, there are additional telephony costs beyond the AI/platform charges: Toll-Free Number Costs: - Monthly fee: $5/month [(1) ]() - Inbound calls: $0.06 per minute These telephony charges are separate from the Conversation Voice Engine costs (which start at $0.07-$0.08 per minute for the AI processing) . [(2) ]() , [(3) ]() So your total per-minute cost would include both the telephony charge and the AI platform charge combined. For the most current and complete pricing details, I'd recommend checking Retell's official [pricing page]() . [(2) ]()

​ To learn more, see the sources I considered: [[1] I’m trying to use a toll-free number (connected from Twilio through a SIP trunk)](https://community.retellai.com/t/i-m-trying-to-use-a-toll-free-number-connected-from-twilio-through-a-sip-trunk/127) [[2] ](https://www.retellai.com/resources/voice-ai-platform-pricing-comparison-2025) [[3] ](https://www.retellai.com/resources/inbound-vs-outbound-callers-pricing-comparison-2025) ​

Feel free to tag @AI Evy with additional questions. I also appreciate feedback, it helps me improve.