Replacing a Phone Receptionist with an AI Voice Agent: The Full Cost Comparison
What does it actually cost to replace a part-time or full-time phone receptionist with an AI voice agent? We run the numbers honestly — including what AI can't replace.
This is a realistic cost comparison based on publicly available salary data and actual AI infrastructure pricing. We're not quoting a specific customer's results — we're showing you the math so you can run it for your own business.
The Scenario
A small professional services firm (accountant, solicitor, clinic, or estate agent) handles roughly 40–60 inbound calls per day. Around 70% of those calls are routine: appointment scheduling, hours and directions, FAQs about services, messages for staff. 30% require a human.
Today, a part-time receptionist handles all of these calls.
What a Part-Time Receptionist Costs
Part-time receptionist (20 hours/week, UK median):
- Salary: ~£12,500–£15,000/year
- Employer NI + pension: ~£1,800–£2,200/year
- Holiday cover (agency): ~£1,000–£1,500/year
- Total annual cost: approximately £16,000–£19,000
- Monthly: £1,333–£1,583
(US equivalent: a 20hr/week receptionist at $16–18/hr = $16,640–$18,720/year including basic payroll overhead.)
What an AI Voice Agent Costs for the Same Volume
50 calls/day × 22 working days = ~1,100 calls/month. Average call length 3 minutes = 3,300 minutes/month.
- Platform subscription: ~£79–£149/month
- AI inference (STT + LLM + TTS at actual API rates): ~£18–£30/month
- Telephony (inbound minutes): ~£20–£25/month
- Total: approximately £117–£204/month
The Direct Comparison
| Part-Time Receptionist | AI Voice Agent | |
|---|---|---|
| Monthly cost | £1,333–£1,583 | £117–£204 |
| Hours covered | 20 hrs/week | 24/7 |
| Simultaneous calls | 1 | Unlimited |
| Sick/holiday cover | Extra cost | Included |
| Training time | 2–4 weeks | Under 1 hour |
| Annual saving | — | ~£13,500–£16,600 |
What the AI Agent Handles (Realistically)
Based on typical SMB call patterns, an AI voice agent can reliably handle:
- ✅ Appointment booking and rescheduling (with calendar integration)
- ✅ Hours, location, parking, directions
- ✅ Service descriptions and pricing FAQs
- ✅ Taking messages and callback requests
- ✅ After-hours coverage (calls the receptionist would miss anyway)
What It Doesn't Handle (Be Honest)
- ❌ Complex complaints requiring empathy and judgement
- ❌ Calls where the customer is distressed or in crisis
- ❌ Highly nuanced conversations with long-term clients
- ❌ In-person reception duties
The right model is hybrid: AI handles the high-volume routine calls 24/7, while your human staff focuses on the calls that actually need them.
The Realistic Outcome
For a firm spending £1,300+/month on phone reception, an AI voice agent handling 70% of calls while escalating the rest to staff represents a realistic saving of £10,000–£14,000/year — while improving coverage (24/7 vs. business hours only) and eliminating missed calls during busy periods.
If you want to run this calculation for your own call volume, start a free trial on OpenVoice Agents. You can test with real calls before committing to anything.