AI phone assistant costs for three business sizes

The bill starts with the subscription and ends with follow-up work

Call volume determines the starting price. In our example of 60 monthly calls, an AI phone assistant costs between €53.70 and €141.61 for the subscription alone. At 720 calls, the range becomes €99 to €284.41. These comparison figures include 19% VAT; setup and human review come on top.

For a small business, I would initially cover only calls received when the line is busy or the office is closed. Keep the task to producing a usable callback note. Count a conversation as completed only when the request, a way to return the call and the next action are clear. Booking appointments or handling concurrent callers requires the corresponding features.

The calculations use regular monthly prices from vendor sources opened on 2 October 2026 and explicitly assumed workloads, rather than measured customer results.

Three billing models need one comparison basis

Vendors count different units. IONOS Flex costs €39 including 30 calls, then €0.49 for each additional call; its unlimited plan costs €99. Both prices include VAT. Call length does not change the subscription total calculated here for this per-call model.

fonio Solo costs €119 before VAT per month for 1,000 minutes. Once those run out, it automatically adds 100-minute bundles at €15 before VAT. Placetel Grow costs €79 before VAT for 750 minutes, plus €9 for the AI phone number and €0.19 per extra minute.

Our comparison uses monthly billing, one assistant phone number, inbound calls and no introductory freebies. We multiply net subscription prices by 1.19 to make the figures comparable. Annual discounts stay outside the calculation. Headcount and call volume are separate inputs: a two-person business can receive more calls than a company with forty employees.

Three monthly workloads show the subscription totals

The examples put the workloads on a common basis. We assume 2.5 billable minutes per call. The business sizes are illustrative scenarios, not industry averages. For each volume we use the lowest-priced applicable tier among the plans considered here; their features still differ.

• 2 people, 60 calls, 150 minutes: IONOS Flex €53.70; Placetel Grow including phone number €104.72; fonio Solo €141.61.
• 10 people, 240 calls, 600 minutes: IONOS All-Flat Advanced €99.00; Placetel Grow including phone number €104.72; fonio Solo €141.61.
• 40 people, 720 calls, 1,800 minutes: IONOS All-Flat Advanced €99.00; Placetel Professional including phone number €255.85; fonio Solo with eight extra bundles €284.41.
• Calculation for 60 IONOS calls: 39 + (60 − 30) × 0.49 = €53.70. For 1,800 Placetel minutes: (149 + 9 + 300 × 0.19) × 1.19 = €255.85.
• These are subscription totals. Charges from your existing carrier for diverting calls, onward transfers, setup and maintenance are not included.

A cheap plan can fail at the second simultaneous call

Concurrent calls change the choice. fonio Solo supports one call at a time. For three concurrent calls, Team lists €359 before VAT with 3,600 minutes, or €427.21 including 19% VAT. The Solo figure in the largest example is therefore not a recommendation for a busy switchboard.

Features also change the budget: IONOS lists calendar booking under Flex Pro and All-Flat. A business needing that feature at 60 calls should compare the €69 Flex Pro plan rather than €53.70 for Flex. A callback note and a booked appointment are different deliverables.

Choose one workflow before choosing a vendor: record a message, enter an appointment or transfer to a person. Our guide to phone assistants for trades explains those differences. For businesses taking both sales and service calls, our car dealership guide covers separate phone numbers.

Abandoned calls need their own budget line

An early hang-up can leave the callback note unusable. The three price sources do not clearly establish whether it earns a credit. Do not automatically budget zero. Ask the vendor this specific question: what is charged when someone hangs up after twenty seconds, stays silent or repeats the same question three times?

The comparison counts billable minutes rather than just elapsed conversation time. Get written answers on minimum duration, rounding per call and when charging ends after a transfer. A small rounding rule can turn a short conversation into a full billing unit. Sensitivity example: if 720 calls lasting 2.5 actual minutes each were individually rounded to three minutes, that would be 2,160 billable minutes. Placetel Professional would then cost €336.55 including VAT; this rounding is an assumption, not a confirmed tariff rule.

Onward transfers deserve a separate line. Placetel charges €0.05 before VAT per minute for external destinations. An assumed 100 transfer minutes add €5 before VAT, or €5.95 including VAT. Your existing carrier may also charge for diverting the original number. Silence is rarely a business model.

Setup belongs in the first-year budget

Setup consumes staff time even without an installation invoice. Our budget example allows four internal hours at €60 each: €240 for the call flow, callback destinations and test cases. Add one monthly hour of review at €60. These are our planning assumptions, not a Thümmler AI quote.

For outside help, Placetel’s price list gives an example of €290 before VAT for three setup hours. An external fee replaces only the work included in that engagement; the business still needs to approve the result.

Using fonio Solo from the middle scenario, now before VAT and including internal work: €119 subscription + €60 review + €240 ÷ 12 setup = €199 a month in year one. Assuming 192 usable notes from 240 calls, that is €1.04 per usable note. Dividing the subscription alone by all calls gives 119 ÷ 240 = €0.50, which conceals that difference.

Keep this checklist beside each quote

A complete calculation needs seven filled-in lines. Copy this list for each quote and mark missing information as “not stated.” An empty cell is not a free service. The final line prevents a cheap package from looking successful while callbacks remain unresolved.

• 1. Regular month: subscription €___; includes ___ calls or ___ minutes; VAT included: yes/no.
• 2. Extra usage: price ___; bundle size ___; rounding per call ___; unused allowance expires ___.
• 3. Phone charges: number ___; diversion to assistant ___; onward transfer ___; concurrent calls ___.
• 4. Setup: one-off external fee €___ plus ___ internal hours × €___.
• 5. Ongoing work: ___ review hours; updates €___; additional software €___.
• 6. Failed calls: twenty seconds ___; silence ___; technical fault ___; credit rule ___.
• 7. Outcome: total monthly cost €___ ÷ ___ usable callback notes = €___ per result.

Start with a tightly scoped phone trial

A narrow trial protects the budget. Start with one phone number and a defined period. Write down ten cases to run through: an ordinary callback request, an unclear name, a missing number, a repeat caller, an abandoned call, silence, an out-of-scope question, a transfer, an unavailable destination and an appointment request. Record the outcome, billed unit and follow-up work for each.

Does the assistant automatically pay for itself above a certain call volume? No. If its notes are unusable or nobody returns the calls, an unlimited plan still produces no result. Must you commit for a year immediately? Not for this comparison. Consider a longer commitment only after the workflow works.

Today, take your call log for the last four weeks, put call counts and durations into the seven lines and request written answers for any missing billing rules. For help setting up the conversation and handover, see our AI phone assistant service.