How the math works
There are only three numbers, and all of them are yours. The calculator multiplies your unanswered inquiries in a month by what an average job is worth to you. That product is the most those inquiries could have been worth if every single one had turned into a booked job. We call it the upper bound, because it is one.
If you know your close rate (of the inquiries you answer and quote, the share that book), the calculator multiplies the upper bound by it to give a lower figure: what those inquiries would have been worth had they closed the way your answered ones do. The honest answer sits somewhere between the two, which is why the result is a range and not a single number. Both are multiplied by 12 for the year.
There is no industry average hiding in the formula, no assumed close rate and no multiplier for lifetime value or referrals. Those would make the number bigger and less believable.
Why "at stake" and not "lost"
Not every unanswered caller was a job. Some were price shoppers, some were outside your area, some called three companies and would have picked someone else anyway. Calling the whole figure "lost" would overstate it, so we don't. What the figure does tell you is the size of the opportunity sitting in the gap between the phone ringing and someone picking it up.
Counting unanswered inquiries
The count is the number that matters most, and the easiest one to guess at. Don't guess. Open your phone system's missed-call log for a normal week and count the calls nobody returned. Add the web forms, chats and texts that went more than an hour without a reply. Multiply the week by about 4.3 to get a month. If your work is seasonal, do it once in a busy month and once in a quiet one; the gap between the two is often the story.
What to do with the number
If the low end of the range would pay for a part-time dispatcher or an answering service several times over, the fix is usually cheaper than the leak. Start with the hours the phone goes unanswered most, often early mornings, lunch and after five, and decide who owns those calls. Put a same-hour reply on web forms. Then count again in a month and see whether the number moved.
If you would like someone to go through it with you, our revenue leak remediation work starts with this calculation, done together on your real call logs, and moves on to estimates that never got followed up. For more on the reasoning, read what a missed call actually costs.