What do no-shows cost you?

• Empty slots a month: appointments per week, times 4.33 weeks, times the no-show rate.
• Lost each month: those empty slots times the average price.
• Lost each year: appointments per week, times the weeks you work, times the no-show rate, times the average price.
• Back each year: the yearly loss times the share you think you could fill again.

It only counts the price of the appointment. The real cost is higher: the product you'd have sold at the till, the client who'd have come back next month, the half hour you spent waiting.

Take last month. Count the appointments where the client neither came nor warned you, then divide by the appointments you had booked. Twelve no-shows out of 160 bookings is 7.5%.

Keep late cancellations apart. A client who warns you at 8 a.m. leaves you a chance to fill the slot; one who never turns up doesn't. OnTime's dashboard counts the two separately once you mark who didn't come.

• A reminder the day before with a way to cancel. It turns some no-shows into cancellations, and a slot freed the day before can still be booked.
• Cancelling in one tap instead of a phone call. Clients who have to ring often don't.
• Booking the next visit before the client leaves, while they have their diary open.

The evidence is clearest in health care: a Cochrane review found that text message reminders raise attendance compared with no reminder, on evidence it rated low to moderate in quality. Measure your own rate before and after rather than trusting anyone's average.

OnTime sends the reminder at noon the day before, with a cancel link that puts the slot back on your booking page. How the reminders work.