How Much Does Retell AI Cost? Per-Minute Maths for a Phone Agent

Retell AI charges pay-as-you-go from $0.07 to $0.31 a minute, built from a voice platform fee of $0.055, a speech fee of $0.015 to $0.10, a language-model fee that varies widely, and telephony at $0.015. A typical mid-range agent costs roughly $0.15 a minute, before anyone builds it for you.

Retell is a platform, not a finished receptionist. Its price is what the engine costs to run per minute; the agent itself, its script, its tests and its upkeep are someone's time, and that someone is you or a builder you pay. The maths below covers both halves, then sets the result against two finished services, Goodcall and Smith.ai.

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How the per-minute price is built from parts

Retell's pricing page shows a range of $0.07 to $0.31 a minute, then breaks it down into components. When I read it in November 2026, the parts for a standard voice call were:

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The headline range appears to cover the voice, speech and model parts together, with telephony listed separately, so build your own total from the rows, as below. Models change monthly, so I describe them by price tier instead of name; pick the tier on the page when you build. Speech-to-speech models, which do the listening and talking in one step, are priced separately: the page lists most of them at $0.07 to $0.38 a minute (one is $0.05 plus a separate model fee), so they are not automatically cheaper than the three-part build.

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Optional extras priced per minute or per use

Retell also lists add-ons. Most small agents need at most two or three:

There are monthly items too: $2 a month for each Retell phone number, $20 a month for Retell SMS, $10 for a verified phone number (one table on the page calls it monthly and another a one-time fee, so confirm which), and $8 a month per extra concurrent call beyond the 20 included. A knowledge base is free for the first ten, then $8 each a month. For a small business with a handful of simultaneous calls, concurrency is usually a non-issue.

The worked example: a security installer taking 900 minutes a month

Illustration only. A security installer's main line gets about 300 calls a month averaging three minutes, so 900 minutes of conversation. The owner wants the agent to answer, take the caller's details, answer a few questions from a short price and coverage sheet, and book a survey. Three plausible configurations for the same 900 minutes:

The Lean column uses an assumed $0.010 for a cheap language model, to show the shape; read the actual figure from the page. The Standard column is where I would start: a mid-priced model, the knowledge base for the price sheet, and the safety extras. The Premium column shows how fast a voice upgrade and a heavier model double the bill for the same calls, so buy them only if a test call proves the cheaper setup is not good enough.

Billing is to the nearest second with no per-call rounding, according to Retell's pricing FAQ, so the 900 minutes above is a fair guide. If a call is transferred to a person, the AI fee stops and only the telephony fee carries on.

Then add the builder: the cost the pricing page cannot show

Retell's price assumes the agent exists. Someone has to write the script and conversation flow, connect the knowledge base, link the calendar or CRM, set the handover to a person, and test it with real calls. If that someone is a freelancer, add a one-off build cost and perhaps a monthly maintenance fee. I cannot verify a market rate for either, so here the numbers are assumptions for the sum: say a 12-hour build at $75 an hour ($900 one-off), spread over a year ($75 a month), plus $50 a month for a few hours of upkeep and fixes.

Notice the row for the extra tool. Builders often connect Retell to a calendar, a CRM or an automation service, each of which may carry its own fee. Make the builder list every service the agent touches and who pays for it, and put your own login on each. A hiring checklist for your first AI automation specialist covers the questions to ask.

Against Goodcall and Smith.ai for the same month

Now the comparison that matters to a business owner. Finished services bundle the engine, the build and the upkeep. The published prices I checked were:

• Goodcall: plans of $79, $129 and $299 a month for 100, 500 and 2,000 unique customers. Its page equates 100 customers with about 150 calls, and it bills per unique caller, so repeat calls from the same person do not add to the count. Extra customers cost 79, 26 and 15 cents by plan.
• Smith.ai AI receptionist: free for 25 calls then $3 a call, and Pro plans at $150, $270 and $500 for 75, 150 and 300 calls.

For 300 calls, which might be about 200 unique callers on Goodcall's own ratio, the maths is:

On this volume, the finished service at $129 beats the built agent at $283.60 while the build is amortised, and the Smith.ai tier costs more than either. After the first year the build cost drops out and Retell Standard falls to $208.60, still above Goodcall. So when does Retell win? Three situations: your volume is far higher, so the per-minute rate dominates; you need something a finished service will not do, such as custom call logic or integrations; or you can build and maintain it yourself, so the builder lines disappear. To go deeper on the others, see what counts as a unique caller on Goodcall and Smith.ai pricing for 50, 150 and 300 calls.

Break-even: at what volume does Retell win?

A simple break-even compares Retell's total monthly cost with a finished service. Using the Standard configuration at $0.174 a minute and the assumed $75 build amortisation plus $50 upkeep ($125 of fixed cost), against a Goodcall-style price of $129 for up to 500 customers:

• At 300 minutes a month: $52.20 + $2 + $125 = $179.20. Goodcall wins.
• At 900 minutes: $283.60. Goodcall wins unless you exceed its customer count.
• At 2,000 minutes (roughly 650 calls): $348 + $2 + $125 = $475. Goodcall's $299 plan for up to 2,000 customers is likely cheaper unless callers repeat a lot or you need features it lacks.

The result is a surprise to many owners: at small-business volumes, a finished service is usually cheaper once the builder is counted. Retell makes sense when call logic is unusual, or volume is far higher, or you or an employee will build and maintain it. Per-call pricing from services such as Smith.ai changes the picture again for very low volumes, as covered in how much an AI receptionist costs for a small business.

A second example: outbound reminder calls

Retell's extras matter more when the agent dials out. Say the same installer wants the agent to call 200 customers a month to book their yearly service check. Each call is short, about a minute, and about a third go to voicemail. The sum, using the Standard parts from above:

The surprise is that the conversation itself is under half the bill. The branded-call add-on and the SMS subscription cost more than the talking. If the owner drops branded calls and sends confirmations from the calendar tool instead of Retell SMS, the month falls to $35.80. Each extra is a decision, not a default. Also decide what the agent does when it reaches voicemail: leaving a long message burns minutes, so a short fixed one, or none, is cheaper.

A budget for the build and test period

Before the agent takes a live call, you will spend on testing. A sensible allowance for the installer's inbound agent, using assumed hours and the Standard rate:

1. Script and knowledge base: the builder writes the opening, the questions to ask and the answers from your price and coverage sheet. Allow about four of the twelve assumed hours.
2. First ten test calls: you or the builder call from different phones, in different moods, including a caller who interrupts and one who asks something off-script. At two minutes each that is 20 minutes, about $3.50.
3. Fix and retest: expect two or three rounds. Another 30 test calls adds about $10.
4. Soft launch: forward only after-hours calls for a week, with a person reviewing every transcript each morning.
5. Full launch: the main line, with the handover phrase and the maximum call length set.

The test minutes are trivial next to the builder's hours, which is why those hours, not the per-minute price, are what to haggle over. A builder who can show you the transcript of every test call is easier to trust than one who tells you it works.

Costs that appear only after go-live

• Test calls. Every test call is billed minutes. Fifty tests of two minutes is 100 minutes, about $17 at the Standard rate. Cheap, but it adds up during a long build, so budget a test allowance.
• Long calls. A confused agent that loops adds minutes. Set a maximum call length and a handover phrase so a stuck call goes to a person.
• Voicemail and silence. Outbound calls to voicemail still consume minutes unless the agent detects it and hangs up.
• Text messages. $0.01 each plus $20 a month for Retell SMS, if you use it for confirmations.
• Prices that move. Models and add-ons change; recheck the page every quarter and tell the builder to do the same.

A realistic mistake: pricing on the headline minute

An owner reads "from $0.07 a minute", multiplies by 900 and budgets $63 a month. The builder then delivers a Standard agent with a better voice and a knowledge base, which runs at about $0.17 a minute: $156 a month before the phone number. The gap, nearly $100, is not a trick. The headline is the cheapest combination of parts, and nobody actually runs it.

The way to catch this is simple: ask the builder for the per-minute cost of each part in the proposed configuration, add telephony, and multiply. The table earlier in this tutorial is the template. If the builder will not show the parts, you cannot check the bill.

A quote checklist for a Retell builder

Please quote for a Retell phone agent for [business].
For each item give the price or write "included":
1. Build: script, flow, knowledge base setup, handover rules
2. Per-minute configuration: voice, speech, model tier, add-ons,
   and the resulting cost per minute
3. Telephony: Retell numbers or our own carrier, and who pays
4. Any other service the agent connects to (calendar, CRM,
   automation), its monthly price, and who owns the account
5. A test plan of at least 15 calls, with written results
6. Maximum call length and the handover phrase
7. Maintenance: what is covered monthly and what is extra
8. Handover: Retell and other logins in our name; a guide for
   editing the script and the price sheet
9. How the agent behaves if the knowledge base has no answer

For a ready-made test plan to run before it takes real calls, borrow the 15-call test for a plumber's voice agent and swap in your own questions.

Check a configuration with an AI assistant

If your builder sends a configuration, paste the list of parts into an assistant and ask it to do the arithmetic and flag oddities:

Below is a proposed phone-agent configuration with per-minute
prices. Add the parts into a single cost per minute. Then calculate
monthly cost for 300, 900 and 2,000 minutes. List any part that
looks unusually expensive compared with the others, and any part
that is missing (telephony, speech, voice platform fee). Do not
invent prices; if a part has no price, write "not stated".

[paste configuration]

An illustrative result catches the two commonest gaps: telephony missing from the total, and a premium voice quietly doubling the speech line. If you would rather decide between building and buying with someone alongside you, that is what my AI implementation consultation covers.

Reading the first month's usage against your estimate

When the first month ends, compare three numbers with your sheet: total billed minutes, average cost per minute and the count of calls. A quick check for the installer's Standard agent:

• Billed minutes far above 900 for 300 calls means calls are running long. Read the longest ten transcripts for loops or silences.
• Average cost per minute above $0.18 means an extra is switched on that you did not plan, or a premium voice or model is in use. Ask the builder which.
• Calls well under 300 means the agent is not getting the traffic you forecast. Check the forwarding rules before blaming the agent.

Keep a one-line note of each variance and its cause. After two or three months you will have a cost per call, which is the number to use when you compare Retell against any per-call service.

The decision in four questions

1. How many minutes a month, honestly? Count calls and average length from your phone bill.
2. Does a finished service already do what I need? If yes, price it first.
3. Do I or my team have the time to build and test? If no, add a builder to the Retell figure.
4. Does anything about my calls need custom logic, such as unusual transfers or integrations? If yes, Retell's flexibility starts to earn its cost.

Answer those and you will know whether the $0.07 to $0.31 headline is the right place to start, or whether a published monthly price for a finished service is the cheaper, simpler route.

Retell AI cost questions

Is there a monthly fee for Retell AI?

Retell's pay-as-you-go plan has no platform fee on its pricing page; you pay per minute, plus small monthly items such as $2 per phone number and $20 for Retell SMS. Enterprise is custom priced. Check the page on the day you build, because the list of models and extras changes often.

Do transferred calls keep costing the AI fee?

No. Retell's pricing FAQ says that once a call is transferred, the AI voice agent fee stops and only the telephony fee continues for the rest of the call. It also says calls are tracked to the nearest second, with no rounding up per call.

Can I use my own phone number to avoid telephony charges?

Retell's pricing page lists no charge for SIP trunking or custom telephony, and no charge for custom phone numbers. You then pay your own carrier instead, so compare that bill with Retell's $0.015 a minute telephony rate before assuming it saves money.

Is Retell cheaper than Goodcall or Smith.ai?

Per minute, usually yes. In total, it depends on who builds and maintains the agent. Goodcall and Smith.ai include the build and the upkeep in their price; with Retell you pay a builder or spend your own hours. The worked example below puts the three side by side.

Further reads

• Goodcall vs Rosie: Unique Callers or Minutes, Which Costs Less? — Compare per-caller billing with per-minute billing on real volumes.
• Goodcall Alternatives: When Per-Caller Billing Stops Paying — Find out when per-caller billing stops paying off.
• AI Receptionist for Tradespeople: What It Costs and When It Pays — See what a finished AI receptionist costs a trade business.
• Restaurant AI Voice Agent: 12 Test Calls to Run Before Go-Live — Borrow a twelve-call test plan before any agent takes real calls.
• Aircall Pricing per Minute: AI Voice Agent Rates, Bundles, Limits — What Aircall's AI Voice Agent really costs at 200, 500 and 2,500 minutes a month, and where a bundle starts to beat pay as you go.
• AI Tools and AI Development: The Complete 2026 Guide — the AI hub, including every tutorial in the AI-for-business series.

Sources: Retell AI pricing page and pricing FAQ (retellai.com/pricing), Goodcall pricing page, Smith.ai AI receptionist pricing page.