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.
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, from $0.70 to $2.40 per extra call.
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 |
| Synthflow | $0.09/min | Voice engine only — LLM + telephony additive |
| Trillet | $0.12/min | Flat plan, all-in |
| ServiceAgent | $0.15/min | 15 credits/min at $0.01/credit |
| My AI Front Desk | $0.25/min | 25 credits/min at $0.01/credit |
| Phonely | $0.30/min | Stated $0.25–$0.35/min |
| 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. Retell’s $0.07/min is the published floor of a $0.07–$0.31/min range that moves with your model choice. Synthflow’s $0.09/min is the voice engine alone, with the LLM ($0.02–$0.05/min) and telephony additive. If you want a marginal rate you can actually trust, Trillet’s flat $0.12/min on Studio and Agency, or ServiceAgent’s $0.15/min, are all-in numbers that don’t sprout footnotes.
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. The same logic appears on per-call plans below.
Per-call overage is a different unit — and Smith.ai is the outlier
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.
The unfriendly end is Smith.ai at $2.40 per extra call — and unlike a per-minute rate, it doesn’t matter whether the call ran twenty seconds or six minutes; you pay $2.40 either way. On the Starter plan’s 30 included calls, your eleventh call past the bucket has already cost more than a whole month of Upfirst Starter. Smith.ai also stacks a $3/call live-agent handoff on top if a human takes over, which is its own line item.
The human services are the ceiling, and that’s the point
PATLive sits at the top because a person picks up. Its overage runs $2.60/min on Basic down to $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 — three numbers matter. Vapi’s $0.05/min is the cheapest marginal minute but the least all-in. Trillet’s $0.12/min and ServiceAgent’s $0.15/min are the cheapest trustworthy, all-in marginal minutes. And Dialzara’s $0.48→$0.35/min taper rewards you for committing before the busy season, not after. Per call, Upfirst’s $0.70–$1.50 undercuts Smith.ai’s flat $2.40 by a wide margin — unless you specifically want the human handoff Smith.ai sells. The headline price is what a slow month costs. The overage rate is what success costs, and it’s the one worth shopping.