AI Receptionist Pricing Explained: Per-Minute vs Flat Rate
The two models look similar on the proposal and behave very differently on the invoice.
Published 21 June 2026 by the Boafo Agent team
Most AI receptionist vendors offer either per-minute or flat-rate pricing. On a glossy proposal they look comparable. On a real invoice they behave very differently. We have watched customers save thousands by switching models and watched others get caught out by switching the wrong way.
This article is the plain-English guide to the trade-off, with worked examples for low, medium and high call volumes. By the end you will know which model fits you and which questions to ask the vendor before you sign.
How the two models actually behave
Numbers from real customer bills.
- £0.50 to £1.20Typical per-minute rate range
- 3.5 minutesAverage AI receptionist call length
- 200 callsVolume above which flat-rate usually wins
- 30%Average savings of flat-rate vs per-minute at mid-SMB volume
- 2x to 5xVariance in monthly per-minute bills due to peak season
- 0%Variance in flat-rate monthly cost; predictability is the whole point
Practical examples
Low volume: per-minute often wins
A solo accountant with 50 calls a month averaging 4 minutes each pays roughly £200 a month on per-minute pricing at £1 per minute. Flat-rate at this band is often £199 to £249. Per-minute marginally wins.
But the variance can sting. A busy month at 90 calls doubles the per-minute bill. Flat-rate stays steady. Choose based on your tolerance for variance, not just the median price.
Mid volume: flat-rate wins clearly
A four-van trades business with 600 calls a month at 3.5 minutes average burns £2,100 a month on per-minute at £1. Flat-rate at this volume sits around £350 to £500.
The flat-rate plan is dramatically cheaper and predictable. Trades owners told us they switched within a quarter once they ran the numbers.
High volume: flat-rate is the only sane choice
A multi-site dental group running 2,800 calls a month at 3 minutes average would burn £8,400 a month on per-minute. Flat-rate at this volume is around £700 to £1,200.
Per-minute pricing at scale is a wealth-transfer mechanism from customers to vendors. Volume customers should always negotiate flat-rate.
Industry use cases
Solo professionals
Per-minute or low flat-rate. Either works. Choose based on call variance.
Trades and home services
Flat-rate from day one. Volume varies and per-minute punishes spikes.
Healthcare
Flat-rate, always. Peak-season variance is destructive on per-minute.
Multi-site operators
Flat-rate with negotiated volume tiers. Push for unlimited bands.
Common mistakes to avoid
- Mistake 1
Picking per-minute because it looks cheaper on a single test month
Always model six months of variance, not one.
- Mistake 2
Not asking about overage rates on flat-rate plans
Some flat-rate plans charge punitive overage above the band. Know the number before you sign.
- Mistake 3
Forgetting that AI call length is not human call length
AI calls are typically 30 to 60% shorter than human calls. Do not import human-call assumptions into your model.
- Mistake 4
Ignoring peak-season impact
Per-minute bills can triple during peak. Flat-rate does not. The choice is essentially insurance.
- Mistake 5
Locking into a year-long contract
Monthly rolling is standard in 2026. Hold out for it.
Compare the two models on your data
Use the cost calculator to model both. We will share the spreadsheet on request.
Frequently asked questions
Is one model objectively better?
No. Per-minute can win at very low volume. Flat-rate wins almost everywhere else.
What if my volume is unpredictable?
Flat-rate, every time. Predictability has real value.
Do flat-rate plans have hidden caps?
Some do. Read the small print on overage rates and minute caps.
Can I switch models later?
Usually yes. Ask the vendor explicitly before signing.
Is there a hybrid model?
A few vendors offer a base plus minutes. Often the worst of both worlds for SMB.
What about pay-as-you-go?
Same as per-minute in practice. Same trade-off.
Where to go from here
The right next step depends on the product you need.