How many baristas do I need per hour of service?

There is a rule of thumb, and it depends more on your menu and your machine than on the number of seats: one barista handles about 60–80 espresso drinks an hour on a two-group machine with an automatic grinder, if someone else takes payment and does food. Alone on the whole shop, that drops to 35–45.

A planning table owners use, for a specialty café doing mostly milk drinks:

How to get your own numbers instead of the table:

1. Pull hourly transaction counts from the till for four weeks. Convert to drinks (most tickets are 1.4–1.8 drinks in a café).
2. Time your bar: how many drinks can your best barista make in a busy 20 minutes without quality dropping? Multiply by three. That is your real capacity per person on your machine.
3. Staff to the 80th percentile hour, not the busiest hour of the year. Accept a queue on the three busiest Saturdays.
4. Layer shifts: a 6:30–2:30 opener, a 9–5 mid, a 12–8 closer covers a 14-hour day with three people and two-person peaks.

Things that cost more than a barista and fix more: a second grinder (removes the 8am bottleneck), a milk-steaming assistant for the volume shop, and a till that takes tap payments in three seconds instead of eight. Half of "we need another barista" is really "the till is slow".

Roughly, budget labour at one hour of paid time per 25–35 drinks sold across the whole day, then tune from your own till data after a month.