A human answering service suits a small business whose calls are few, varied, emotionally sensitive or worth a lot each. An AI receptionist suits a business with steady or high call volume and predictable call types, which needs every call answered around the clock at a lower cost per call. Often the best answer is a mix: AI answers first, and people take the calls the AI should not handle.
The rest of this guide explains how each option works, what drives the cost and where each one falls short. It then shows how to decide using your own call data rather than a sales pitch.
What each option actually is
Human answering service
A human answering service, sometimes called a virtual receptionist service, sends your calls to a team of trained receptionists who work for a third party. They greet callers in your business name, take messages, and screen and transfer calls. Some also book appointments or complete intake forms. You pay for their time or for each call they handle.
AI receptionist
An AI receptionist is software that answers the phone with a synthetic voice. It turns the caller's speech into text and uses a language model to work out what the caller wants. It replies using text-to-speech, then takes an action: it answers a question, books a slot, takes a message or transfers the call.
There are two ways to get one. You can subscribe to an off-the-shelf product, or you can have a system built for you on your own infrastructure. A custom build involves a build cost rather than only a monthly fee, but it gives you control over the logic. That control matters more than many buyers expect (see "Who controls the call logic" below).
How the cost models differ
The two options are priced in different units, and that difference often decides the comparison before quality does.
- Per-minute pricing. Ruby, a well-known US human receptionist service, sells plans by minutes per month. Its published plans run from 50 minutes for $250 a month to 500 minutes for $1,725. One third-party analysis reports that Ruby rounds each call up to the next 30-second increment, so a 31-second call is billed as a full minute. The same analysis says spam and wrong-number calls are billable unless filtered, and that overage runs at roughly $3.30 to $5.40 a minute depending on the plan.
- Per-call pricing for humans. Smith.ai prices its human virtual receptionist service per call. Its published Starter plan is 30 calls for $300 a month, with overage at $11.50 a call. Its Pro plan is 300 calls for $2,100, with overage at $8.50.
- Per-call pricing for AI. Smith.ai's AI receptionist has a free tier that includes 25 calls a month, with extra calls at $3.00 each. Its Pro plan costs $150 a month with calls at $2.00 each, and its Enterprise tier lists $1.67 a call at higher volumes.
On the same vendor's published rates, an AI-answered call costs a fraction of a human-answered one. Prices change, so check current rates before you budget. Also check what counts as a billable call. Smith.ai says spam and wrong-number calls do not count towards the quota on its human plans. On its AI plans, up to 10% of monthly calls can be removed from billing as spam. A service that bills you for robocalls and wrong numbers can cost far more than its headline rate suggests.
What drives the real cost
- Call volume and length. Per-minute plans penalise long calls, and per-call plans penalise many short ones.
- Billing increments. Rounding every call up to a fixed increment raises the effective rate, especially if many of your calls are short.
- Add-ons. Smith.ai's human plans list extra per-call charges of $0.25 to $1.50, for example for booking appointments, extended intake questions or call recording and transcription.
- Overage. A busy month can push you into overage rates that are higher than your plan rate. Price your worst month, not your average.
- Escalation. If an AI service transfers difficult calls to human agents, check how those calls are charged.
- Build and maintenance, for a custom system. A custom AI receptionist has a build cost plus running costs for telephony, speech and model usage. In return, you are not paying a vendor's margin on every call, and you own the system.
Where a human answering service is the better choice
- Low call volume. If you take a handful of calls a week, AI saves you little in absolute terms, and a human service is simple to set up.
- Calls that need judgement or empathy. A person handles these calls better: distressed callers, complaints, bereavement, medical worries or legal emergencies. An AI that misreads the caller's tone in these calls can damage the relationship.
- Unpredictable call content. If no two calls are alike, an AI will often end up transferring calls or taking messages, which removes most of its value.
- High value per call. When one call can be worth thousands in fees, the extra cost of a human answer is easy to justify.
Where an AI receptionist is the better choice
- Repetitive questions. Opening hours, prices, service areas, booking changes and order status are well suited to AI.
- Out-of-hours and overflow calls. AI does not work in shifts, so it can answer at 3am or during a lunchtime rush.
- Volume spikes. Software can be set up to take several calls at once. A human service has a fixed number of staff on duty.
- Structured actions. If a call should end with an entry in a calendar, CRM or ticketing system, AI can make that entry directly through integrations. Nobody has to retype a message.
- Consistency. The AI follows the same rules on every call. That helps when you need the same questions asked in the same order, for example to qualify leads.
In a voice receptionist we built, the problem was simple. Calls do not stop when the office closes, and each one still needs someone to pick up, work out what the caller wants and send them to the right place. The system answers every call, day or night, on the client's existing phone number, then classifies each call and routes it. You can read more in the AI voice receptionist case study.
Hybrid set-ups
The choice is rarely all or nothing. Common set-ups include:
- AI first, human fallback. The AI answers every call and handles routine requests, then transfers anything outside its rules to a person. Smith.ai, for instance, lets AI-answered calls be passed to live receptionists at any hour.
- Humans in hours, AI out of hours. Your own staff or a human service covers the working day, and AI covers evenings, weekends and holidays.
- AI for overflow. Staff answer when they can, and the AI picks up when lines are busy or after a set number of rings.
The key design decision in any hybrid is the escalation rule. Write down which call types must always reach a person, such as complaints, emergencies, high-value existing clients and anyone who asks for a human. Then test that the AI follows those rules.
Compliance points to check
Telling callers they are speaking to AI (EU)
Under Article 50 of the EU AI Act, AI systems that interact directly with people must be designed so that people know they are dealing with AI, unless that is obvious from the context. This information must be given clearly at the first interaction at the latest. These obligations have applied since 2 August 2026. In practice, open each call with a short statement that the caller is speaking to an automated assistant. It is sensible practice in the UK and US as well.
Outbound calls and callbacks (US)
In February 2024 the US Federal Communications Commission confirmed that AI-generated voices count as "artificial" voices under the Telephone Consumer Protection Act. As a result, calls that use them generally need the prior express consent of the person being called. This mainly affects outbound calls. If your AI receptionist will also make callbacks, reminders or follow-up calls, get legal advice on consent before you switch that on.
Recording and data protection
Both options record or transcribe calls, and both process personal data. Ask any provider where recordings and transcripts are stored, how long they are kept and who can access them. Also ask whether they are used to train the provider's models. UK and EU businesses should make sure a data processing agreement is in place and that callers are told the call may be recorded.
Who controls the call logic
Each option changes its behaviour in a different way:
- Human answering service: you update a script and rely on every receptionist following it.
- Off-the-shelf AI product: you can change only the settings the vendor exposes.
- Custom-built system: you change the logic directly.
This matters once your needs grow. In the receptionist we built, the deciding fact was that a managed voice platform decides how your calls behave. So classification and routing run on our own server, where the logic is ours to change, and speech-to-text and text-to-speech run through a single provider. If you expect to add call types, connect new systems or switch voice providers later, ask any vendor how much of the routing you can change yourself.
How to decide: a practical checklist
- Pull a month of call data. Count calls by hour, length and type. Most phone systems can export this.
- Sort calls into categories. For example: routine questions, bookings, sales enquiries, existing-client issues, complaints and spam. Estimate the share of each.
- Mark the calls that must reach a person. These set the minimum level of human involvement.
- Price both options on your real numbers. Use your busiest month, include add-ons, overage and billing increments, and check how spam is billed.
- Check the integrations. Find out whether the option can write to your calendar, CRM or ticketing system, or whether someone will have to retype messages.
- Run a pilot. Start with out-of-hours or overflow calls. Listen to recordings weekly, track how many calls are transferred or abandoned, and adjust.
- Agree an exit. Know how you will get your recordings, transcripts and configuration back if you leave.
Common mistakes
- Comparing headline plan prices without checking billing increments, add-ons and how spam is billed.
- Letting an AI handle sensitive call types because it handled routine ones well in a demo.
- Leaving out the AI disclosure at the start of the call.
- Treating set-up as a one-off job. Scripts and AI rules both need reviewing whenever your services, prices or hours change.
If you want to see what an AI receptionist would look like on your own phone number and systems, Khive builds AI voice agents in code and hands them over, so you own the system and its logic. Send us a brief with your call volumes and the call types you want covered, and we will tell you what we would build.
Sources
- Ruby: Plans and pricing
- Ruby Receptionists Pricing Guide (Vida)
- Smith.ai: Virtual Receptionist Pricing
- Smith.ai: AI Receptionist Pricing
- EU AI Act Service Desk: Article 50 Transparency obligations
- The EU AI Act's transparency rules: A practical guide to Article 50
- Cooley: FCC: AI-Generated Robocalls Illegal Under the TCPA
- Mayer Brown: FCC Declares Authority and Intent to Regulate AI-Generated Calls Under the TCPA
