Guide · AI Receptionists
AI receptionist overage rates run from $0.05 a minute to $2.60 — a 50x spread for the exact same overflow
The price of going over your plan is the price you should shop on, because it's the number that moves when business is good — and in this dataset it spans more than fifty-fold.
Re-checked 2026-09-09 — and the vendor that had gone quiet came back louder. Smith.ai publishes self-serve per-call pricing again, and the June note in this guide is superseded: read first-party on 2026-09-09, its page carries no Managed plan and no $2.40 anywhere. The flat rate this guide used as its per-call ceiling has become a six-rung ladder — $3.00 on a new free tier, then $2.50, $2.30, $2.17 on both 300-call rungs, and $2.10 on the sales-led Enterprise 500 — which leaves Smith.ai’s free plan holding the highest published per-call rate in the whole index. The index also gained its 25th vendor: CallSprout Sage, metered at $0.39/min with zero bundled minutes, so its overage rate is its only rate. One June finding carries forward intact and one is a loose end. ServiceAgent repriced its credit to $0.02–$0.04, putting its real marginal minute at $0.30–$0.60 rather than $0.15 — re-verified 2026-09-02, unchanged. Synthflow is the loose end: a 2026-06-22 read found self-serve pricing pulled for custom enterprise contracts from $30,000/yr, but the later 2026-06-27 read our dataset carries records Pay As You Go at $0.09/min for the voice engine, so the $0.09 is what the record stands behind until the page is read first-party again. The pattern the last re-check named holds, and now runs both ways — vendors retire cheap published rates, and they reinstate dear ones.
The sticker price tells you what a quiet month costs. The overage rate tells you what a good month costs — and that’s the one to negotiate on, because the included bucket is exactly what you’ll outgrow when the phone starts ringing. In this dataset the marginal price of one extra minute spans more than fifty-fold: $0.05/min on Vapi at the bottom, $2.60/min on PATLive at the top. Per-call plans tell the same story in a different unit: Upfirst’s published rate runs $0.70 to $1.50 per extra call, while Smith.ai’s rebuilt ladder starts above where Upfirst’s ends and climbs to $3.00 per extra call on its free plan.
Two things drive that gap: who answers, and whether the overage rate is “all-in.” Here is the per-minute field, cheapest marginal rate first.
| Vendor | Overage rate | What the rate covers |
|---|---|---|
| Vapi | $0.05/min | Platform fee only — models passed through on top |
| Retell AI | $0.07/min | Published floor of a $0.07–$0.31/min range |
| Trillet | $0.12/min | Flat plan, all-in |
| My AI Front Desk | $0.25/min | 25 credits/min at $0.01/credit |
| Phonely | $0.30/min | Stated $0.25–$0.35/min by plan |
| ServiceAgent | $0.30 → $0.60/min | 15 credits/min; credits now $0.02–$0.04 each |
| CallSprout Sage | $0.39/min | Every Sage minute — nothing is bundled; free first 30 s of each call; base is $22.95 per user seat |
| Dialzara | $0.48 → $0.35/min | Tiered; cheaper rate on higher plans |
| PATLive | $2.60 → $2.00/min | Live human agents |
The developer platforms own the floor, but the same caveat that haunts their sticker prices haunts their overage rates. Vapi’s $0.05/min is the platform fee; the language model, speech-to-text, and text-to-speech are billed on top, so one extra minute costs more than five cents in practice (we unpack that gap in the true per-minute cost of the developer voice platforms). Retell’s $0.07/min is the published floor of a $0.07–$0.31/min range that moves with your model choice. Synthflow sits right here too, at $0.09/min for its voice engine alone — LLM ($0.02–$0.05/min) and telephony additive — which is the figure our dataset carries from a 2026-06-27 read. An earlier read on 2026-06-22 had found self-serve pricing pulled for enterprise-only quotes from $30,000/yr; the later read contradicts it, so the $0.09 stands until the page is read first-party again, and the table above is a row short because of that unresolved conflict rather than because Synthflow publishes nothing. If you want a marginal rate you can actually trust, Trillet’s flat $0.12/min on Studio and Agency is now the cleanest all-in number on the board: it doesn’t sprout footnotes. ServiceAgent reads cheap at a glance too, but it is the clearest example of the footnote trap — 15 credits a minute sounds fixed, yet a credit now costs $0.02–$0.04, which puts its real marginal minute at $0.30–$0.60, not the $0.15 a one-cent credit would imply.
The tiered plans reward growth — quietly
A flat overage rate is honest but static. Dialzara does something subtler: it steps the overage down as you climb plans — $0.48/min on Business Lite, $0.45 on Pro, $0.40 on Plus, $0.35/min on Elite. The included bucket grows too (60 minutes to 1,000), so the more you commit, the less every extra minute costs. We walk the tier-by-tier overage savings on Dialzara in detail separately. Smith.ai now does the same thing per call, from a much greater height, and the per-call plans below show what that looks like.
The vendor with no bucket to blow through
Every rate above is what you pay after something runs out. CallSprout Sage — the 25th vendor in this index and the newest — has nothing to run out: it bundles zero Sage minutes, so its $0.39/min isn’t an overage rate at all. It is the only rate, running from the first billable second of the first call.
Three qualifications ride with that number, and none of them are optional. It is metered after the first 30 seconds of every call, by the second, so short calls get a genuine discount the other meters here don’t give: a one-minute call costs $0.195, a two-minute call $0.585 — an effective $0.29 a minute — and only long calls approach the $0.39 headline. Our cost model can’t express a per-call free window, so it bills every modelled minute and overstates Sage by exactly $0.195 a call; any Sage figure we model is an upper bound, not a quote. And a second meter runs alongside the first: AI Transcription at $0.0198/min on live and recorded calls, on every plan (voicemail transcription is free). The page doesn’t say whether a Sage-answered call also incurs that charge, so we leave the overlap unstated rather than assume it either way.
Then there’s the unit under the meter, which is unlike anything else here: $22.95 per user seat per month on Business, $39.95 per seat on Call Center. A five-person office pays $114.75 before a single Sage minute is metered, and Sage is one included feature of a cloud phone system rather than a receptionist subscription sold on its own. That is why its sticker and its bill disagree so loudly. $22.95 is the lowest paid base price in the 25-vendor index — under Upfirst and AIRA at $24.95, ReceptionHQ at $25, Dialzara at $29, with only $0 free tiers such as Smith.ai’s beneath it — yet at our reference workload of 200 calls averaging three minutes, a single seat models at about $257 and ranks fifteenth of the 21 vendors we can price there. The meter decides the bill, not the seat. That is this guide’s whole argument, arriving in the form of a vendor.
Per-call overage is a different unit — and Smith.ai still owns the expensive end
Three vendors bill the overage by the call, not the minute, which changes how you should read it. Upfirst charges $1.50 per extra call on Starter, dropping to $1.00, $0.75, and $0.70 per call as you move up to Scale. (AIRA publishes a byte-identical table.) That’s the friendly end, and we put the two head to head in Smith.ai vs Upfirst per-call pricing.
The unfriendly end is still Smith.ai — but it is no longer one number, and it is no longer missing. Its self-serve pricing is published again, read first-party on 2026-09-09, and the flat $2.40 this guide used to quote appears nowhere on the page. What replaced it is a ladder of six priced rungs carrying five distinct rates: $3.00 per extra call on the new Free tier (25 real calls included), $2.50 on Pro at 75 calls/mo ($150), $2.30 on Pro at 150 ($270), $2.17 on Pro at 300 ($500) and on the sales-led Enterprise rung at the same 300 calls, and $2.10 on the sales-led Enterprise 500 ($800). Note where those rates sit: Smith.ai’s cheapest extra call, reachable only through a sales conversation, is 1.4x Upfirst’s dearest, which sits on a $24.95 plan.
Two features of that ladder are worth pausing on. The dearest rung is the free one. $3.00 per extra call is the highest published per-call rate anywhere in this index, and it is what a $0 plan charges from its 26th call — a fine way to trial the product and an expensive way to grow inside it. And the meter is still indifferent to length: twenty seconds or six minutes, the rung’s rate is what you pay. On a two-minute call, the $2.30 rung works out at $1.15 a minute, nearly ten times Trillet’s all-in $0.12; on a six-minute call the same rung is $0.38 a minute, a shade under Sage’s metered rate. Same rate, opposite verdicts, and your average call length is what decides which one you get.
One thing does work in the buyer’s favour here, and it is unusual enough to name: calls matching Smith.ai’s 20-million-strong spam list are filtered before they are answered and never count against the bundle, and up to 10% of calls can be credited off each bill as spam. That reduces how many calls are exposed to those rates in the first place — a defence against the overage meter rather than a discount on it.
The human services are the ceiling, and that’s the point
PATLive sits at the top because a person picks up. Its overage steps down the more you commit — $2.60/min on Basic, $2.35 on Starter, $2.20 on Standard, $2.10 on Premium, and $2.00/min on Pro — and on the Basic plan there are no included minutes, so the very first minute is billed at $2.60. That is not the AI market failing; it’s the cost of the thing the AI plans replace. Put PATLive’s $2.00–$2.60/min next to Trillet’s $0.12 and the gap is the AI-versus-human decision, priced per minute.
The cleanest answer: read the rate, not the headline
If overage is your real risk — seasonal spikes, a marketing push, a viral week — a few numbers matter. Vapi’s $0.05/min is the cheapest marginal minute but the least all-in. Trillet’s flat $0.12/min is still the cheapest trustworthy, all-in marginal minute on the board — the kind of number that doesn’t move on you. (ServiceAgent used to share that spot at $0.15/min, but repricing its credit to $0.02–$0.04 pushed its real rate to $0.30–$0.60.) Dialzara’s $0.48→$0.35/min taper rewards you for committing before the busy season, not after. CallSprout Sage’s $0.39/min has no bucket in front of it at all, so it is the rate from the first call — on top of $22.95 per user seat per month, which is a per-seat price in an index of per-business ones. Per call, Upfirst’s $0.70–$1.50 is the friendly end; Smith.ai’s $2.10–$3.00 is the expensive one, now published as a ladder rather than a flat fee, with its steepest rate sitting on its free plan. The lesson sharpens with every re-check: the headline price is what a slow month costs, the overage rate is what success costs — and vendors move it in both directions, quietly, which is why it’s the one worth shopping.