### Answer A single Retell AI voice agent can handle an unlimited number of calls simultaneously [(1) ]() . You don't need to create multiple agents to manage multiple calls concurrently—each agent is capable of handling an unlimited number of calls, provided the total concurrency remains within your workspace's designated quota . Concurrency limits apply per workspace: Pay-As-You-Go workspaces are allocated a quota of 20 concurrent calls by default . If your operational needs require more concurrency, you can adjust your limit from the dashboard . Concurrency Burst feature: When enabled, Concurrency Burst allows you to temporarily exceed your standard concurrency limit during peak demand periods . Your burst limit is calculated as the lower of: - 3× your concurrency limit, OR - Your concurrency limit + 300 For example, if your limit is 50, burst allows up to 150 concurrent calls . If your limit is 200, burst allows up to 500 concurrent calls .

​ To learn more, see the sources I considered: [[1] Understand concurrency & limits](https://docs.retellai.com/deploy/concurrency) ​

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

### Answer When using a Twilio-managed phone number connected via SIP trunk, the same concurrency limits apply [(1) ]() . The concurrency limits are per workspace, not per phone number or telephony provider . Your Retell AI voice agent can still handle an unlimited number of calls simultaneously, as long as the total concurrency across all calls in your workspace stays within your designated quota . Pay-As-You-Go workspaces have a default quota of 20 concurrent calls . Using Twilio with Elastic SIP Trunking doesn't change these limits [(2) ]() [(3) ]() . With Elastic SIP Trunking, Retell AI integrates VoIP-based AI agents with PSTN, allowing seamless inbound and outbound calls while maintaining all Retell-supported telephony features, provided the telephony provider supports them [(2) ]() . If you need more than 20 concurrent calls, you can adjust your concurrency limit from the dashboard [(1) ]() . You can also enable Concurrency Burst to temporarily exceed your standard limit during peak demand periods .

​ To learn more, see the sources I considered: [[1] Understand concurrency & limits](https://docs.retellai.com/deploy/concurrency) [[2] AI in SIP Calling & Telephony Solutions | Retell AI](https://www.retellai.com/blog/integrating-ai-with-sip-trunking-and-modern-telephony) [[3] How to Choose the Right Telephony System in 2024 | Retell AI](https://www.retellai.com/blog/how-to-choose-the-right-telephony-system-in-2024) ​

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