Website Leak Calculator

The Website Leak Calculator turns four numbers you already know into a range: how much extra work your website could be bringing in if the common leaks were fixed. It needs no sign-up and sends nothing anywhere. It sits with our other free tools, and it is written for the owner of a small business rather than a marketer. A second tab, Slow replies and missed calls, works out what enquiries that wait too long are costing you.

A leak, here, is anything that lets a visitor who wanted to get in touch leave without doing so, or lets an enquiry that did arrive go cold. Most small business sites have one or two. Very few owners know which ones, because a lost enquiry leaves no trace in the inbox.

The four numbers it asks for

Visitors a month comes from Google Analytics, or from your website platform’s stats page. Use a normal month, not the one with the local newspaper mention.

Enquiries a month means every call, form and email that came from the website. If you don’t track the source, ask new customers how they found you for a few weeks. Divided by visitors, this gives your enquiry rate, which the calculator shows under the inputs. Our conversion rate calculator will tell you whether that rate is solid or just noise from a small sample.

Average job value is what a typical won enquiry is worth to you. If one customer comes back three times a year, count the year.

Enquiries you win is your close rate. Out of ten enquiries, how many become paid work? Be honest here, because every figure the calculator produces is multiplied by it.

Five leaks worth checking

The calculator lists five. Each one starts with a low and a high assumption, which you can change. None of them is a measurement of your site, and where a published study exists we link to it so you can judge how far it stretches to a business your size.

1. Slow pages on a phone

Plenty of visitors arrive on a phone, often on mobile data. If the page takes a few seconds to show anything useful, some of them go back to the search results and pick the next business. In a 2020 study for Google, 55 and Deloitte tracked 37 large brand sites across more than 30 million sessions and found that a 0.1 second mobile speed improvement went with 21.6% more lead-generation visitors reaching the form submission page (web.dev, updated 24 June 2020). Those were big brands with heavy traffic, so the calculator starts far lower, at 5% to 15%.

To check yours, run the page through our mobile-friendly test, then load it on your own phone with wi-fi turned off.

2. No clear next step on the first screen

A visitor who has decided to call you should not have to scroll to find the number. The first screen on a phone needs one obvious action, whether that is a tap-to-call button or a short form. We could not find a published figure we trust for small sites, so this leak’s range is your judgement alone. A quick test is to hand your phone to someone who has never seen the site and time how long it takes them to find a way to contact you.

3. A contact form nobody has tested

Forms break without warning. A plugin update or an expired email setting can stop submissions arriving while the page still says “thank you”. Nothing lands in the inbox, so nobody notices. The calculator’s range for this one runs from 0% (the form works) to 20% (a fifth of your enquiries were coming through it). Submit your own form today and check the message arrives. Our website launch checklist puts a test submission of every form near the top for that reason.

4. No visible reviews

People check what others say before they pick up the phone. BrightLocal’s survey of 1,002 US adults, published 11 February 2026, found that 97% read reviews for local businesses and 47% would not use a business with fewer than 20 reviews (BrightLocal, Local Consumer Review Survey 2026). That is stated intent in another country, so treat it as a reason to check rather than a number to plug in. If you have good Google reviews and the site doesn’t show them, that one is easy to fix.

5. Slow replies to enquiries

This leak lives after the website, but the website created the enquiry, so it belongs in the sum. In an audit of 2,241 US companies, firms that tried to contact a web lead within an hour were nearly seven times as likely to qualify it as firms that waited longer, and only 37% replied within the hour (Harvard Business Review, March 2011). Qualifying a lead is not the same as winning the job. That is why the calculator applies this leak to your win rate rather than your enquiry count, and starts at a modest 10% to 25%. If enquiries reach you through several channels, a lead management system is how larger firms stop them waiting.

How the sum works

The calculator first works out what the site brings in today: enquiries, times win rate, times job value. Then it recalculates with each ticked leak fixed. Leaks that affect enquiries compound, so two 10% improvements give 21% rather than 20%. The reply-speed leak raises your win rate instead, and the win rate can never go above 100%. The low figure uses every low assumption and the high figure uses every high one.

With the starting numbers (1,500 visitors, 15 enquiries, £1,200 jobs, a 30% win rate, and the speed and reply leaks ticked), the site brings in £5,400 of work a month. Fixing both leaks at the low end gives 15.75 enquiries at a 33% win rate, which is £6,237, so the leaks cost £837 a month. At the high end it is 17.25 enquiries at 37.5%, which is £7,763, a gap of £2,363 a month.

The result is a range on purpose. A single figure would suggest a precision nobody has, and any calculator that tells you your site is losing exactly £4,312 a month is selling something.

Slow replies and missed calls

The second tab is for a different question. The website did its job and the phone rang, or the form arrived, but nobody answered until the next day. A plumber up a ladder misses calls, and so does a solicitor in a meeting. Some of those callers ring the next name on the list.

You give it your enquiries a week, counting calls, voicemails, forms, emails and messages, plus the same job value and win rate as the first tab (change them on either tab and both update).

Then you estimate the share of enquiries lost to slow or missed replies, as a low and a high figure. We know of no published figure for a business your size, so the starting 5% to 15% is only an example. Your phone’s call log is the quickest way to firm it up. Count last month’s missed calls, then how many of those people you got back.

The sum is enquiries a week, times the share lost, times your win rate, times your job value. That gives the work lost each week, and a month is that times 52, divided by 12. It assumes a lost enquiry would have been won at your usual rate. Some would have been tyre-kickers and some the best job of the month, so the average is the fairest guess.

With the starting numbers (8 enquiries a week, £1,200 jobs, a 30% win rate and 5% to 15% lost), each enquiry is worth £360 of work. Losing 0.4 to 1.2 enquiries a week costs £144 to £432 a week, which is £624 to £1,872 a month, or £7,488 to £22,464 a year.

If that figure is bigger than you would like, look at where enquiries land. When every call, form and email arrives in one place and the right person hears about it straight away, fewer of them wait. A lead management system is built to do that.

Frequently asked questions

How do I know how much my website is costing me?

Start with what it earns: monthly enquiries from the site, times the share you win, times your average job value. The cost of a leak is the difference between that and the same sum with the leak fixed. The calculator above does that sum for you with your numbers.

What is a good enquiry rate for a small business website?

It depends on the trade, the price of the job and where the traffic comes from, so a single benchmark misleads more than it helps. Compare your rate with your own past months instead. A sudden drop with steady visitors usually points to something broken, often the form.

Why is my website not getting enquiries?

Either too few of the right people are reaching it, or the people who reach it are leaving. The second group is what this calculator covers. If visitors are low too, that is a search visibility problem, and the free scan shows the basics of that as well.

How much do missed calls cost a small business?

It depends on how many you miss and what a job is worth, which is why the second tab asks for your own figures. Multiply the enquiries you lose each week by your win rate and your average job value. Three missed callers a week who never ring back, at a 30% win rate and £1,200 a job, is about £1,080 of work a week.

What counts as a slow reply?

Slow is whatever lets the customer book someone else first. For an emergency call-out that might be ten minutes; for a conveyancing quote it might be the same afternoon. If you don’t know, ask the last few customers who went elsewhere.

Is my data stored?

No. The calculator runs in your browser and nothing you type is sent or saved.

Can I use it for a law firm, an accountant or a trade business?

Yes. The four inputs work for any business that wins work through enquiries. Only the job value and win rate change from one line of work to another.

Find out which leaks you have

The calculator tells you what the leaks could be worth. Our free website scan tells you which ones your live site has, checking speed, SEO, accessibility and security in one pass with no sign-up. If the scan turns up more than you want to fix yourself, we build and host small business websites with these checks done before launch.