Ask a practice manager what a missed call costs and the honest answer is usually: nobody knows. The phone rang, nobody answered, and the story ends there. The patient's side of the story carries on, at another practice.
Suppliers love to fill that gap with big round numbers. We will not. The most quoted industry figure is that roughly four in five callers who reach voicemail hang up without leaving a message, which is why a missed call rarely turns into a callback. What we can give you is a method that uses your own numbers, which is more useful anyway.
The arithmetic of an unanswered phone
You need three figures, and you already have all of them.
Calls per day. Your phone system logs this. If it does not, that is a finding in itself, and a good reason to look at your telephony before anything else.
The share you miss. Count engaged tones, rings that gave up, and everything that landed on voicemail outside opening hours. Most practices have never measured the out-of-hours share, and it is usually the biggest surprise.
Your average appointment value. Your practice management system will give you this. For new patient enquiries, consider the value of the first course of treatment rather than the first exam alone.
Multiply them: calls per day × 5 working days × 4.3 weeks × share missed × average appointment value. The result is not lost revenue, and we are careful about that distinction. It is revenue exposed to the queue each month: the value of bookings that depended on somebody answering.
Why dental practices feel it most
Dentistry has an unusual profile: high appointment values, patients who shop between practices, and enquiry peaks at lunchtime and in the evening, exactly when reception is thinnest. A missed NHS repeat booking often comes back. A missed private new patient enquiry usually does not.
Run your own numbers
The missed-call calculator does the multiplication for you and shows its working. Every input is yours, and the method note is printed next to the result. If the number surprises you, the fix is simple to test: watch Prime Assist answer a live call.
Every figure in this article is either yours or tokenised pending evidence. We do not publish invented statistics.