Chair utilisation measures how much of the time you could be working is filled with paid work. Take the hours a chair, bed or treatment room is available in a week, take the hours actually booked with clients, and divide the second by the first. A chair open 40 hours and booked for 30 is at 75%. The same sum works for a nail desk, a massage room or a tan booth.
It is one of the most honest measures of whether a business needs more clients, more staff or different hours. High takings with low utilisation mean a few expensive services are carrying a lot of empty time. High utilisation with low takings means the prices or the menu need a look.
In practice
A three-chair salon is open 9 to 5 on five weekdays and 9 to 1 on Saturday: 44 hours per chair, so 132 chair-hours a week. Last week it booked 92 hours of clients, which puts utilisation at 92 divided by 132, about 70%. Split by day, the picture changes. Saturday was full, the Thursday late night was close to full, and Tuesday sat under half.
That split points to the fix. Tuesday does not need more advertising for the salon in general. It needs a reason to book on a Tuesday, a waitlist whose members are offered Tuesday gaps first, or one fewer stylist rostered on. A full Saturday means some callers are being turned away, and the regulars who could come on a weekday are the ones to ask, with a direct offer of a standing time.
Decide your own comfortable ceiling. A day booked solid leaves no room for a late client, a walk-in or a colour correction that runs over.