Quick verdict
Bottom line up front: Retell AI builds AI phone agents that answer and place real calls, and it charges by the minute instead of by the seat: $0.07 to $0.31 a minute all-in, no platform fee, $10 in free credits to start. The catch: every minute stacks four separate charges plus add-ons, so do the math before you commit.
Research-based review — prices checked October 22, 2026. We do not claim hands-on testing.
What does Retell AI do?
Retell AI is a platform for building AI voice agents that handle phone calls: answering support lines, booking appointments, qualifying leads and running outbound campaigns. You design the agent in a visual drag-and-drop builder or through its API, pick a model and a voice, connect a phone number, and it talks to callers in real time — Retell advertises roughly 600ms response latency.
Three choices define every agent. The model is yours to pick — Retell is LLM-agnostic, supporting GPT, Claude, Gemini and open-source models, plus your own fine-tune through the API. The voice can be Retell’s own or come from providers such as ElevenLabs, Cartesia, MiniMax, Fish or OpenAI. And the telephony can run on Retell numbers or on your own SIP trunk through carriers like Twilio or Vonage, so existing business numbers keep working. Production features include warm transfers to a human with a whispered summary, IVR navigation with DTMF keypad input, branded caller ID, batch outbound calling and simulation testing before an agent goes live. Retell lists 55+ languages, and HIPAA, SOC 2 Type I and II, GDPR and ISO 27001 compliance come on every plan rather than behind Enterprise.
How much does Retell AI cost?
| Component | Price | What it means |
|---|---|---|
| Voice agent (all-in) | $0.07–$0.31/min | Pay-as-you-go, no platform fee; the total depends on the model, voice and telephony you choose. New accounts get $10 in free credits |
| Voice infrastructure | $0.055/min | Charged on every call minute |
| Voice | $0.015/min (ElevenLabs $0.040/min) | Retell and most third-party voices sit at the lower rate |
| Telephony | $0.015/min on Retell numbers; $0 with your own SIP trunk | US rate; phone numbers cost $2/month, toll-free $5/month |
| Concurrency | 20 simultaneous calls free, then $8/slot/month | Enterprise plans start at 50+ concurrent calls with custom pricing |
| Add-ons | Knowledge base use $0.005/min; branded calls $0.10/call; batch dials $0.005/dial | First 10 knowledge bases are free, then $8/month each |
Run the math before trusting the $0.07 headline — that floor needs the cheapest model, a standard voice and your own phone infrastructure. A recent line-by-line breakdown of Retell’s pricing page put a typical stack at $0.149 a minute: at that rate, 1,000 inbound calls averaging three minutes cost about $447 a month plus $2 for the number. Speech-to-text is included, and billing is to the nearest second.
What are Retell AI’s strengths?
- No seat tax: pay-as-you-go with no platform fee means a quiet month costs almost nothing — the opposite of per-agent subscriptions.
- Real telephony depth: SIP trunking, warm transfers, branded caller ID, verified numbers and DTMF navigation are built in, not bolted on.
- Model and voice freedom: swap GPT, Claude or Gemini models and voices from six providers without rebuilding the agent.
- Compliance on every plan: HIPAA, SOC 2, GDPR and ISO 27001 coverage plus PII redaction are not Enterprise-only.
- Generous starting capacity: 20 concurrent calls included is more than most metered rivals bundle.
What are Retell AI’s weaknesses?
- The bill stacks: infrastructure, voice, model, telephony and add-ons each add their own per-minute line, so premium models and voices push you toward $0.31 fast.
- No humans of its own: Retell has no in-house backup agents — when a call must escalate, it transfers to your team or nobody.
- It handles the conversation, not the system behind it: booking rules and CRM updates live in tools you connect and wire up.
- Enterprise gates the admin layer: SSO, role-based access control and dedicated support sit on the custom-priced Enterprise plan; pay-as-you-go gets a shared server and community support.
Who is Retell AI for?
Retell AI fits businesses whose phones ring too much or at the wrong hours: clinics and home-services firms booking appointments, support teams drowning in repeat questions, and sales or operations teams qualifying leads and running outbound follow-ups by phone. It is a poor fit if your callers need a human safety net on every call, or if your volume is so low that voicemail-to-text would do the job free.
Frequently asked questions
Is Retell AI free to try?
Yes. New accounts start with $10 in free credits and no platform fee, so you can build and test an agent before paying anything.
Why does the same agent cost different amounts per minute?
Because each minute is a stack: $0.055 infrastructure plus your voice, your language model and your telephony. A budget model with a standard voice lands near $0.07; a frontier model with a premium voice approaches $0.31.
Is Retell AI HIPAA compliant?
Retell lists HIPAA, SOC 2 Type I and II, GDPR and ISO 27001 coverage on every plan, with PII redaction for transcripts and recordings.
Verdict
Retell AI is the voice-agent platform to start with if you want production phone calls without a subscription: the builder is quick, the telephony is genuinely complete, and $10 of free credits buys a real test. Just budget with the mid-range math, not the headline — a well-specced agent costs closer to $0.15 a minute, and at call-center volumes that difference is the whole decision.