For a restaurant owner, cost per booking is what one channel — the phone, your own site, a reservation portal, an aggregator — spends to produce one reservation. Rank the channels by that number and the answer looks obvious. Divide the same cost by guests who actually sat down instead, and the order changes.
Why no channel is free: the phone costs person-minutes
A channel looks free when nobody sends an invoice for it. The phone is the clearest case: no subscription, no commission, no line in the accounting software — and a shift manager who spends a quarter of an hour every hour taking, moving and confirming tables. That time is paid for, so the channel is paid for. The only difference from the portal is who writes the number down.
The conversion is one line, and it is the first thing to run before any comparison:
Channel labour cost = Minutes spent on the channel ÷ 60 × Fully loaded hourly cost
Minutes spent on the channel— minutes of staff time the channel consumes in the period: picking up, calling back, rewriting the book, confirming, minutes;60— minutes in an hour, a pure conversion factor;Fully loaded hourly cost— an hour of that person including employer contributions, PLN per hour. The term belongs to the labour-cost page of this section, and the number is yours, not an industry figure.
Take a month in which the phone consumed 900 minutes and an hour of the person answering costs 45.00 PLN fully loaded. Then 900 ÷ 60 × 45.00 = 675.00 PLN. Nobody invoiced it and it is still the second most expensive channel in the example below.
The same arithmetic already exists for calls that never get answered — a missed call is the same minute, only spent by the guest instead of by you, and the blog piece on the cost of missed calls walks the formula end to end. If the phone line itself is the bottleneck, an AI receptionist changes the minutes per booking, which is exactly the input this page divides by.
Booking channel — a path by which a table gets reserved: the phone, your own site, a reservation portal, a delivery aggregator, the walk-in list.
Why the own-site channel is smaller than it looks
isoc_ciwebn2, section I, enterprises with 10+ persons employed, reference year 2025, data updated 27 February 2026, read 27 August 2026); the EU-27 figures for the same two lines are 76.51 % and 48.01 %.What the pair does say is that for most venues the site is a page, not a channel, and the bookings keep arriving by phone.
What counts as a channel cost and what is the venue's cost
One test settles almost every argument: would this cost disappear if the channel were switched off tomorrow? Gone — it is a channel cost. Still there — it belongs to the venue and gets divided across everything, not charged to one channel.
| Channel | Direct money cost | Cost in person-minutes | What is not a channel cost |
|---|---|---|---|
| Phone | telephony plan, callback SMS | picking up, calling back, rewriting the book | the manager's salary as such |
| Own site | reservation widget subscription, hosting, ads sending traffic to it | checking new requests, confirming | building the site once, general branding |
| Reservation portal | monthly fee, per-cover or per-booking fee | matching the portal book with your own | the table itself and the food on it |
| Delivery aggregator | commission on the order, promo co-funding | packing, handling, resolving complaints | packaging bought anyway for takeaway |
| Walk-in | — | seating and the waiting list | the host's shift |
Two costs are argued about every time. The reservation system subscription is a venue cost when it holds the whole book, and a channel cost only for the channel that cannot exist without it. Advertising belongs to the channel it points at: an ad that sends people to a portal listing is a portal cost, even when you paid for it.
Attributed booking — a booking assigned to one channel by a written rule. The rule matters more than its precision: an unwritten rule changes silently between periods, and then last month and this month are no longer comparable.
Cost per booking: the formula and why the denominator matters more than the numerator
Cost per booking = Channel cost in the period ÷ Bookings attributed to the channel
Channel cost in the period— direct money plus person-minutes converted by the line above, PLN;Bookings attributed to the channel— bookings the written rule gives to that channel in the same period, a count.
Cost per booking — channel cost for a period divided by bookings attributed to that channel in the same period.
Everything hard about this formula is on the right-hand side. The numerator is invoices and a stopwatch. The denominator is a decision: bookings taken, or bookings that turned into guests. Take one month, three channels, and figures that are an illustration of the method rather than any benchmark:
| Channel | Channel cost, PLN | How that cost is made up | Bookings taken | No-shows | Bookings seated |
|---|---|---|---|---|---|
| Phone | 675.00 | 0 invoiced + 900 min | 180 | 20 % | 144 |
| Own site | 240.00 | 150.00 subscription + 120 min | 120 | 10 % | 108 |
| Reservation portal | 810.00 | 690.00 invoiced + 160 min | 180 | 15 % | 153 |
Cost per booking taken: phone 675.00 ÷ 180 = 3.75 PLN, own site 240.00 ÷ 120 = 2.00 PLN, portal 810.00 ÷ 180 = 4.50 PLN. Check it backwards — 3.75 × 180 = 675.00 — and the ranking reads: the site is cheapest, the portal is dearest, the phone sits in the middle. That is the number most venues stop at, and it is the number that is about to change places.
Cost per seated cover: how no-shows reorder the channels
Cost per seated cover = Channel cost in the period ÷ Covers actually seated from the channel
Covers actually seated— guests who arrived and sat down, a count, not the guests who were written into the book;Channel cost in the period— the same PLN as above, unchanged.
Cost per seated cover — the same channel cost divided by guests actually seated from it, the version no-shows cannot flatter.
Add party size to the same month: the phone books 2.0 covers per seated booking, the site 2.5, the portal 3.0. Seated covers are then 144 × 2.0 = 288, 108 × 2.5 = 270 and 153 × 3.0 = 459.
| Channel | Cost per booking taken, PLN | Seated covers | Cost per seated cover, PLN | Rank change |
|---|---|---|---|---|
| Phone | 3.75 | 288 | 2.34 | 2nd → 3rd |
| Own site | 2.00 | 270 | 0.89 | 1st → 1st |
| Reservation portal | 4.50 | 459 | 1.76 | 3rd → 2nd |
The phone and the portal swap places, and nothing about the invoices changed. Two things moved: the share of bookings that never arrived, and how many people each booking brings. A channel with a high no-show rate is a channel you pay for twice — once for the booking and once for the empty table-hour it reserved.
The empty table-hour is a separate measure with its own page: table turnover and what a no-show takes out of the room counts the loss in seat-hours, which is what the room feels, while this page only uses the no-show share as a correction to a denominator. The chain of confirmations that moves that share is described in the blog piece on no-shows, and whether a deposit pays for itself is the subject of the deposit page.
Attribution: the guest saw the portal and phoned — whose channel is that
This is where cost per booking stops being arithmetic and becomes a policy. The same guest can be produced by two channels, and if the rule is not written down, the answer drifts with whoever is entering the booking that evening.
Three rules that are all defensible
Last touch gives the booking to the channel that carried the actual reservation — here, the phone. Simple, reproducible, and it undercounts the channels that create demand. First touch gives it to the portal that was seen first; it flatters discovery and needs a way of knowing what was seen. Assisted counts the booking once for the phone and marks the portal as an assist in a second column, never adding the two into one total.
The rule you can actually run
Pick the one your staff can execute in three seconds while a guest waits on the line. In practice that means one added question at booking time and one field in the book. Whatever you choose, write it in one sentence, date it, and change it only between periods — never inside one.
Where a shared queue helps
When phone, forms, messengers and the portal each keep their own list, the same booking is counted twice and the same minutes are paid for twice. Bringing them into one queue instead of five is what makes the denominator countable at all; the same is true of web forms and messenger channels, which are only channels once their requests land in the same book as everything else.
What a booking contributes to margin once the channel cost is removed
Cheapest is not the same as best. A channel is worth what it leaves behind after the food, the packaging and the fee it carries.
Contribution margin — the money left from net sales after variable costs, available to cover fixed costs and, once they are covered, to become profit. The definition and the ratio belong to the break-even page of this section and are quoted here word for word; this page does not redefine them.
Net contribution per booking = Contribution margin per cover × Covers per booking − Cost per booking
Contribution margin per cover— the contribution one seated guest leaves, PLN per cover;Covers per booking— seated covers divided by bookings taken for that channel, covers per booking, so the no-show is already inside it;Cost per booking— the PLN per booking calculated above.
Both terms are brought to PLN per booking before the subtraction. With a contribution margin of 38.00 PLN per cover in the same example month:
| Channel | Seated covers per booking taken | Margin per booking, PLN | Cost per booking, PLN | Net contribution per booking, PLN |
|---|---|---|---|---|
| Phone | 1.60 | 60.80 | 3.75 | 57.05 |
| Own site | 2.25 | 85.50 | 2.00 | 83.50 |
| Reservation portal | 2.55 | 96.90 | 4.50 | 92.40 |
Third ranking, third answer: the dearest channel per booking leaves the most money on the table it fills. That is not an argument for portals, it is an argument against ranking channels by one number.
What a channel gives beyond the table: guest data, the repeat visit, the review
Two channels can cost the same per seated cover and still not be worth the same, because one of them hands you a guest you can invite again and the other hands you an anonymous cover.
| Channel | Guest data stays with you | You can invite them back | Who owns the review |
|---|---|---|---|
| Phone | yes, if it is written down | yes | nobody — it is never asked for |
| Own site | yes, with consent | yes | you ask, on your terms |
| Reservation portal | partly, by the portal's rules | only inside the portal | the portal |
| Delivery aggregator | rarely | through the platform | the platform |
| Walk-in | only if you ask | rarely | the map listing |
A booking that leaves a contactable guest behind is an input to a different calculation entirely — what one new guest costs to acquire lives on the acquisition cost page, and this page stops at the booking. What a platform keeps and what stays with you is set out in the piece on online orders. Where all of this has to be readable in one place, that is a job for reporting and analytics rather than for another spreadsheet.
A dearer channel that brings a different guest — when that is worth paying for
isoc_ec_eseln2, section I, enterprises with 10+ persons employed, reference year 2025, data updated 15 June 2026, read 27 August 2026).The same caveat applies: section I is accommodation and food service together, hotels included, ten or more people employed.
Commission cost per order = Commission rate × Order value on the base the contract names
Commission rate— the rate written in your contract, as a decimal fraction between 0 and 1;Order value— the order total on the base the contract names, PLN — with or without VAT is something to read, not to assume.
A 120.00 PLN order at a rate of 0.25 costs 0.25 × 120.00 = 30.00 PLN in commission; dividing back, 30.00 ÷ 120.00 = 0.25. The rate here is an arithmetic example and nothing else: no official statistics publish aggregator commission rates, so the only defensible source is the contract you signed. Which base that rate is applied to — gross or net — changes the answer and has its own page: the delivery margin after commission takes the base apart. This page takes the rate as an input and stops.
So when is dearer worth it? When the channel brings covers you would not otherwise have, at a party size you cannot fill from your own list, in hours your room is empty. A portal cover on a dead Tuesday and a portal cover on a full Saturday are the same cost and completely different decisions.
What to do in one week to collect these numbers without a new system
Nothing here needs software you do not have. It needs one sheet with four columns and one written rule.
Days one to five
Keep a tally next to the book: channel, bookings taken, bookings seated, covers seated. Have whoever answers the phone note the minutes in blocks of five; a rough count of minutes is a real number, and an absent one is not. Add invoices from the portal, the widget and the telephony plan at the end of the week.
Day six
Do the three divisions in this order: cost per booking, cost per seated cover, net contribution per booking. Do not skip the second one — it is the one that reorders the list.
Day seven
Write the attribution rule in one sentence and date it. Then decide one thing only: which single channel gets attention next month. If the site is the cheapest channel and the smallest, a booking flow that actually takes reservations is the cheapest capacity you can add; a full picture of what else can be automated around it is in the restaurant automation overview.
Everything on this page is arithmetic — division, multiplication and one written rule. Nothing here is done by artificial intelligence, and nothing here needs it. AI belongs one step earlier, where the minutes are spent: answering the call, confirming the table, chasing the confirmation. It changes the inputs of these formulas; it does not calculate them.
Frequently asked questions
How do I calculate cost per booking for the phone channel?
Count the minutes the phone consumes in a period, convert them at the fully loaded hourly cost of the person answering, add any telephony and SMS invoices, then divide by the bookings the phone produced in the same period. In the example above that is 900 minutes at 45.00 PLN an hour, 675.00 PLN over 180 bookings, 3.75 PLN per booking.
Why does dividing by seated covers change which channel is cheapest?
Because no-shows and party size are not distributed evenly across channels. Dividing by bookings taken credits a channel for tables that were never occupied; dividing by covers actually seated does not. In the example the phone and the portal swap places without a single invoice changing.
A guest found us on a portal and then phoned — whose booking is it?
Whichever your written rule says, and the fact that it is written matters more than which rule you picked. Last touch gives it to the phone, first touch to the portal, assisted attribution counts it once for the phone and notes the portal in a second column. What you must not do is decide it case by case.
Is the commission taken from the gross or the net order value?
Whatever the contract says, and it must be read rather than assumed, because the same rate on two different bases gives two different amounts. Take the base from your own agreement; the arithmetic of that base is taken apart on the delivery margin page of this section.
Should the reservation system subscription be split across channels?
Only if the system serves one channel. If it holds the whole book for phone, site and portal alike, it is a venue cost and splitting it across channels only moves the same money around. If a channel would not exist without it, it belongs to that channel entirely.
What does a channel give beyond the booking itself?
Guest data you may contact again, a review you can ask for, and a repeat visit you can plan. Two channels with the same cost per seated cover are not equally valuable if one leaves you a contactable guest and the other leaves an anonymous cover.
Do the four-column tally for one week, run the three divisions, and read the list from the bottom rather than the top: the channel that looks dearest per booking is often the one paying for the room. The other pages of the restaurant section pick up where this one stops — the margin after commission, the cost of acquiring a guest, and what a deposit does to the denominator.