AI phone assistant for restaurants: 1.59 euros per booking

The monthly fee is the smallest line item

The subscription price decides nothing here. For its phone assistant SIA, Gastronaut quotes 29 euros a month, 1.29 euros per booking and 0.15 euros per started minute. Assume a booking call runs two started minutes: 0.30 euros of call time plus the 1.29 euro booking fee, so 1.59 euros per accepted booking. A call that ends without a booking, a cancellation say, costs 0.15 euros.

Against that sits the contribution a table makes. Take 70 euros of revenue per booking and a food cost ratio of 30 percent, both set here as example values, and 49 euros are left, because the staff are in the building during service anyway. The 29 euro fee is therefore paid off after 0.61 extra bookings a month, which is to say after the first one.

Stopping there answers the wrong question. With this pricing model the cost side barely matters; the decision turns on whether the assistant lands guests nobody else would have taken.

A part-timer costs 46 cents for the same call

On the main line the AI is the more expensive tool. The statutory minimum wage has been 13.90 euros an hour since 1 January 2026, which is 23.2 cents a minute and 46 cents for a two-minute call, before employer contributions. The assistant charges 1.59 euros for the same conversation, a factor of 3.5.

That inverts the sales pitch. An AI phone assistant saves a restaurant no wages at all while somebody is in the building who could pick up. It earns its money purely on calls that would otherwise have rung out, and vendor pages never run the sum in that direction.

Margin pressure is what makes the difference measurable. According to a DEHOGA release of 26 May 2026, hospitality revenue from January to March 2026 was 5.1 percent below the same period a year earlier in real terms and 19.7 percent below 2019, while energy, food and labour costs have risen by up to 35 percent since early 2022.

Three sizes of business, counting missed calls only

This table counts only calls nobody would have answered. It assumes a 60 percent conversion rate, 70 euros of revenue per booking and 30 percent food cost; the charges come from the SIA terms above. The rows were computed with python3 and rebuild with your own figures in the same formula: result equals bookings times 49 euros, minus 29 euros, minus bookings times 1.59 euros, minus remaining calls times 0.15 euros.

• Small bistro, 60 missed calls a month: 36 bookings, charges 89.84 euros, contribution 1,764 euros, result 1,674.16 euros
• Mid-sized restaurant, 180 missed calls: 108 bookings, charges 211.52 euros, contribution 5,292 euros, result 5,080.48 euros
• Large venue, 400 missed calls: 240 bookings, charges 434.60 euros, contribution 11,760 euros, result 11,325.40 euros
• Threshold in all three cases: the monthly fee is covered from 0.61 extra bookings a month
• Counter-check on the main line: those same 60 calls cost a part-timer 22.24 euros in wages instead of 89.84 euros in fees

The threshold is the conversion rate, not the price

On the main number the AI has to beat a person. If a person takes 70 of 100 calls during service, set here as an assumption, the assistant only wins above a 70 percent conversion rate. At 60 percent the house loses 10 bookings per 100 calls, at 50 percent it loses 20. Conversion is not a feeling: it is inbound calls against bookings entered in the reservation system.

One week of your own data produces that figure. Gastronaut bills per booking, so the invoice lists exactly the completed transactions, and the per-minute line next to it shows how many conversations ended with nothing.

Other vendors sell minute bundles instead of per-booking fees. Ruf Paula quotes Solo with 150 minutes at 99 euros, Team with 350 at 199 euros and Premium with 1,000 at 499 euros. Under that model an abandoned call costs exactly as much as a successful one, which makes conversion matter even more. Hey Gastroline, by contrast, publishes no prices at all and describes its own pricing logic as still being settled.

Between six and nine in the evening the case is clear

During service the phone rings when nobody has a hand free. In those three evening hours calls arrive alongside the pass in almost every house, and a call that rings three times and hangs up is lost outright. There, every booking taken is a gain against zero, not against a person.

In practice: do not divert the main number, add a second one and let the main line overflow to it after the fourth ring. Add the hours after closing and the weekly closing day. Nobody picks up on a closing day, and Friday's booking gets decided on Tuesday.

Lunchtime is different. Anyone standing at the pass at midday with the phone within reach gives away 1.13 euros per booking, the gap between the fee and the 46 cents of minimum wage for the same call.

Four things that flip the sum

These four turn a gain into a loss. They are ordered by how often they occur, with the most expensive last.

• No-shows: the assistant also accepts the booking nobody keeps. Without the SMS confirmation and reminder Gastronaut lists as add-ons, the contribution per accepted booking falls while the 1.59 euro fee stays.
• Allergies and intolerances: those are health data, and Article 9(1) GDPR prohibits processing them in principle. Capturing them by phone requires explicit consent under paragraph 2 point (a). Simpler: do not ask, and move the question to the table.
• Special cases: parties of eight or more, set menus and birthday tables belong with a person. Set that limit in the system rather than leaving it to the model.
• The greeting: the AI Act has applied since 2 August 2026, and Article 50(1) requires the caller to learn they are dealing with an AI system unless that is obvious. Article 113 sets that date of application.

What I would do in your place

I would put the assistant on overflow only. In practice: a second number, overflow after four rings, live between six and nine in the evening, after closing and on the closing day, with SMS confirmation and a cap of seven people per booking. The main number stays as it is during the day.

Yes, if the house takes bookings, calls regularly go unanswered during service, and a reservation system exists for the assistant to write into. No, if the house works without bookings, if guests mostly book at the table or through a platform, or if the assistant only writes to an inbox instead of the table plan: then it moves work around rather than doing it.

What splitting the numbers looks like in another trade is in our piece on car dealerships. The cost of a missed call in a workshop is in car repair shops, and turning tokens into euros per transaction is in AI cost per transaction.

Common questions

What does the assistant really cost per month? At 108 accepted bookings and 72 further calls, the SIA terms come to 211.52 euros. The reservation system itself is billed separately at Gastronaut, where the Basic tier with 750 included placements costs 89 euros a month by the vendor's own figures.

Is it worth it for a 30-seat bistro? Yes, if calls there regularly go unanswered in the evening. At 60 missed calls a month the sum above gives a result of 1,674.16 euros. No, if somebody sits by the phone in the evening, because then the bistro overpays by 1.13 euros per booking.

The prices are vendor list prices as of 25 September 2026, and the two assumptions on call length and food cost are example values, not survey results.

The next step

Count your missed calls for a week before booking anything. The phone system or the mobile provider reports missed calls by hour; log only the window between six and nine in the evening, plus the closing day and the hours after closing. Multiply that count by 0.6 and by your own contribution per table, and you have the upper bound of the benefit.

If the figure comes in under 100 euros a month, leave it. If it comes in above, listen to our AI phone demo to hear how such an assistant sounds; setup, the greeting and the link into the table plan are described under our AI phone assistant service.