You are on a roof, under a sink or inside an attic. Your phone rings, and you cannot answer it. The caller waits for a few rings, then calls the next company in the search results. You may never find out that call existed.
This guide gives you a formula to put a dollar figure on that, shows a worked example, and explains how to get the inputs from your own phone instead of guessing.
The formula
Monthly revenue lost = missed calls per week x 4.33 x booking rate x average job value
Here is what each part means.
- Missed calls per week. Real customer calls you did not pick up and did not return in time. Leave out sales calls, wrong numbers and existing customers who only wanted an invoice.
- 4.33. The average number of weeks in a month (52 divided by 12).
- Booking rate. The share of those callers who would have hired you if you had answered. This is the number owners most often guess, so we show how to measure it below.
- Average job value. What a typical new job pays you in revenue. For some trades this is a service call. For others it is a full install or a roof, so use the figure that matches the calls you miss.
A worked Example
Example These figures are made up to show the arithmetic. They are not a benchmark.
| Input | Example value |
|---|---|
| Missed calls per week | 10 |
| Booking rate | 30% (3 in 10) |
| Average job value | $600 |
10 x 4.33 = 43.3 missed calls a month. At 30%, that is 13 jobs. At $600 each, that is $7,794 in revenue, or roughly $7,800 a month.
Now change one number. If only 15% would have booked, the answer halves to about $3,900. If your average job is $250, it falls to about $3,250. The formula is simple, so the whole question is how honest your inputs are. A calculator that hides its formula is selling you something. This one shows it.
How to get your own numbers
You do not need software to find these. You need two weeks and your phone’s call log.
Missed calls per week
Open your call history and count the inbound calls marked missed. Then remove the ones that are not customers. If your phone system or carrier app shows call logs, use that. If you have a Google Business Profile, its performance section may also show call activity, though it only counts calls made from the profile.
Booking rate
For two weeks, call back every missed customer call and write down the result in one of three words: booked, still open, gone. “Gone” means they already hired someone. Your booking rate is booked plus a fair share of still-open, divided by the total. This takes more effort than guessing, and it is the number that matters most.
Be fair about it. A callback an hour later will recover more than a callback the next morning. The rate you measure is the rate for your current speed, which is exactly what you want to improve.
Average job value
Pull your last 20 new-customer invoices and average them. Use the same type of job the missed calls were about. If emergency calls are most of what you miss, use emergency job values, not your yearly average.
Why the loss is bigger than one job
The formula counts one job per caller. It leaves out two things, and both push the real cost up.
- Repeat and referral value. A customer you booked may call again next year and may recommend you. Skip that and you undercount.
- Reviews. Every completed job is a chance for a Google review. Fewer jobs means fewer reviews, and fewer reviews make you harder to choose the next time. Our guide on getting more Google reviews covers that side.
On the other side, not every lost call is recoverable. Some callers were price shopping and would have left anyway. That is why you use a measured booking rate and not 100%.
Where calls get missed
Trades businesses tend to lose calls in the same four places.
- During a job. You cannot or should not answer with your hands busy.
- After hours. Evenings and weekends, when many emergencies start.
- At peak times. Two calls at once, and the second goes to voicemail.
- While driving. Safe to ignore, costly to forget.
Each one has a fix that does not mean hiring a full-time receptionist: forward unanswered calls somewhere useful, text people back, or have an AI receptionist answer. We compare these in AI receptionist for plumbers, and the text option has its own guide: missed-call text-back explained.
What to do with the number
Once you have a monthly figure, compare it with the cost of fixing the problem. Do not treat the result as a promise of what you will recover. Plan for recovering a part of it.
- If the figure is a few hundred dollars a month, a text-back and a good voicemail greeting may be enough.
- If it is a few thousand, answering calls matters. An AI receptionist that picks up overflow and after-hours calls, takes the job details and texts a booking link is built for that gap.
- Measure again after 30 days. The same formula, with a lower missed-call count, shows whether the change worked.
The AI Voice Wizard is how Biz Up handles this: it answers calls you cannot, says it is an AI assistant, captures the job and the address, and sends you a summary. It is part of the AI Voice + Review Wizard plan.
A note on honesty
Anyone who tells you that a specific percentage of missed calls turns into booked jobs has not seen your phone. Your trade, your area, your prices and your speed all change the answer. Measure, then decide.