How much are missed calls costing your plumbing or HVAC shop? Work it out with your own numbers

You will find plenty of articles that put a big number on missed calls. Most of those numbers have no traceable source, and none of them are about your shop. The useful answer comes from four numbers you already have or can estimate in an afternoon: how many new callers you missed, how many of them you never reached, how often you book a caller you do reach, and what a typical job is worth. This guide walks through the calculation and points out where people usually fool themselves.

If you'd rather not do it by hand, our missed-call ROI calculator runs the same math, and the free missed-call audit pulls the first two numbers from your call log.

Step 1: count missed calls from new callers

Start with a month of calls from your phone system or call tracking export. Keep inbound calls that nobody answered, including voicemails. Then remove three groups that inflate the count:

• Existing customers and vendors. A supplier calling about an order isn't a lost job. If your phone system shows first-time callers, use that; otherwise compare numbers against your customer list.
• Repeat calls. Someone who called four times in ten minutes is one person.
• Spam and robocalls. Anything you'd never call back.

What's left is missed calls from new callers. That is the only group where a job is at stake.

Step 2: subtract the ones you did reach

Many missed callers get a callback and book anyway. They're not lost. For each missed new caller, look for an outbound call to the same number after the miss. If there's one, note how long it took. If there isn't, that caller was never reached.

Speed matters here. The most cited research on response time, published in Harvard Business Review in 2011, found that companies that tried to contact a lead within an hour were nearly seven times as likely to qualify it as companies that waited longer. It studied web leads rather than phone calls, but the direction holds for a homeowner who called about a problem. Source: Harvard Business Review, "The Short Life of Online Sales Leads".

For the calculation, treat two groups as at risk: callers never called back, and callers called back late (pick your own cutoff; many shops use one hour during business hours, first thing next morning after hours).

Step 3: use your own booking rate

Your booking rate is the share of new callers your team actually talks to that turn into a booked visit. Most field service software reports it, and many CSR managers track it on a whiteboard. If you have no number, take a week of answered new-caller calls and count the bookings.

Don't borrow an industry average here. Booking rates vary with the trade, the season, the call source and the person answering. Your own number from a normal week is worth more than any benchmark.

Step 4: use your own average first ticket

Use the average invoice for a first visit from a new customer, not your average across all jobs. A replacement sale inflates the average; a diagnostic or repair is a more honest starting point. If you want to reflect replacement opportunities, do it as a separate, smaller line instead of mixing it in.

Step 5: multiply, then be honest about it

The math is one line:

missed new callers never reached (or reached late) × booking rate × average first ticket = revenue at risk per month

Here is an example with made-up numbers, so you can see the shape. Assume 40 missed new callers in a month, of which 15 were never called back and 10 were called back more than an hour later. Assume a booking rate of 50% on calls you answer and an average first ticket of $400. These are assumptions for illustration, not industry figures.

Counting only the 15 never reached, the assumption above gives 15 × 50% × $400 = $3,000 a month at risk. If you also count half of the 10 late callbacks as lost (another assumption), add 5 × 50% × $400 = $1,000.

Two cautions. Not every missed caller would have booked even if you had answered; that's why the booking rate is in the formula. And not every unreturned caller is lost forever; some call again. The result is an estimate of exposure, not a bill. Its real use is to compare months and see whether the number goes down after you change something.

How many calls go unanswered in home services?

Invoca, a call tracking vendor, reports from its own platform that across home services, 52% of calls are answered by a person, 65% for calls longer than 15 seconds, and 73% for calls over 30 seconds, with answer rates ranging from 32% to 74% across sub-industries. Its methodology describes a dataset of over 70 million calls. Source: Invoca's Home Services Lead Conversion Benchmarks Report 2026.

Use those figures to sanity-check your own count, not to replace it. If your call log shows far fewer missed calls than that suggests, check whether voicemails and quick hang-ups are being counted.

Where the money usually leaks

When shops run this calculation, the at-risk callers tend to bunch up in a few places: lunch hours when the CSR is away, the first hour after opening when voicemails pile up, and evenings when calls forward to a tech's cell. Look at the time of day of your unreturned callers before you decide what to fix. A lunch-hour gap needs a different answer than an after-hours one; our guide on after-hours calls covers the second.

Get the first two numbers from your call log

Steps 1 and 2 are the tedious part. Export last month's calls from your phone system (Excel or CSV) and drop the file into our free missed-call audit. It counts missed new callers, shows which have no callback on record and how long the others waited. It runs in your browser and the file isn't uploaded. Then plug your booking rate and average ticket into the ROI calculator.

Sources

• Harvard Business Review, The Short Life of Online Sales Leads (March 2011): https://hbr.org/2011/03/the-short-life-of-online-sales-leads
• Invoca, Home Services Lead Conversion Benchmarks Report 2026: https://www.invoca.com/reports/the-invoca-home-services-lead-conversion-benchmarks-report-2026