Website ROI calculator

1. Enter your average job value — the typical invoice, not your best-ever one.
2. Enter your gross margin: what is left after materials and direct labour, before overhead.
3. Enter the share of enquiries you convert into paid work.
4. Enter what the website costs to run each month, and any one-off build cost.
5. Enter how many extra enquiries a month you honestly expect it to produce — start pessimistic.
6. Read the breakeven, then set the expected enquiries to zero to see the downside squarely.

The single most useful thing here is the pessimistic run. Set expected enquiries to zero. If the resulting annual loss is one you could absorb without noticing, the decision is easy regardless of the upside.

Search for a website ROI calculator and most of them will happily tell you that your investment will return four hundred and eighty percent. They arrive at that by asking you to enter how many extra customers the website will bring, and then multiplying. The output is your own guess, dressed as an analysis.

The honest position is that nobody knows how many enquiries a website will produce for a specific business in a specific town, and anyone who says otherwise is selling websites. Traffic depends on competition you cannot see, search volume you have not measured, and a ranking process nobody outside Google fully understands.

What can be calculated exactly is the hurdle. Given your job value, your margin and your close rate, the arithmetic for how much extra work a site must produce to cover its cost is simple, certain, and specific to you. That number is genuinely decision-relevant: if the hurdle is a tenth of a job a month, you barely need to believe in the website at all for it to be worth doing.

If a job invoices at five hundred dollars and costs you two hundred and seventy-five in materials and direct labour, the website did not earn you five hundred dollars by producing it. It earned you two hundred and twenty-five, and out of that comes your overhead.

This matters more than it sounds. A business working on thirty percent margins needs three times as many extra jobs to cover the same cost as one working on ninety percent. A consultant and a kitchen fitter can pay the same for a website and be in completely different positions.

Most owners overstate their gross margin by five to ten points, usually by forgetting their own unbilled hours on a job or the material wastage they have stopped noticing. If the number you typed came from feel rather than from an invoice, run the calculation again five points lower and see whether the conclusion changes.

Set the expected extra enquiries to zero. What you are left with is the real downside: twelve months of running cost, plus whatever you paid to build it, spent on something that produced nothing measurable.

For a self-built site on a free tier with a domain, that number is around fourteen dollars. It is not a risk in any meaningful sense; the decision is closer to whether you can spare an evening. For a three-thousand-dollar agency build with a retainer, the downside is several thousand dollars and it deserves genuine thought about whether the traffic exists to justify it.

This is the actual shape of the website decision for most small businesses, and it is almost never framed this way. The question is not whether websites work. It is whether the version of the website you are considering has a downside you could shrug off — because if it does, you should stop analysing and go and build it, and if it does not, you should build the cheap version first and let it earn the right to the expensive one.

The calculator asks about extra enquiries, which quietly assumes the website's contribution is a stream of new strangers. For a local business, a large part of the actual value is different and invisible: the referral who was given your name, looked you up before calling, and decided you looked real.

That person would have appeared in your figures as a referral either way. If the site had not existed, or had looked abandoned, some proportion of them would not have called at all — and you would never have known, because a call that does not happen leaves no trace.

There is no honest way to put a number on that here, so we do not try. But it is worth knowing that the calculator is conservative for exactly this reason, and that the effect is largest for businesses whose work comes mostly from word of mouth — which is to say, for most small businesses.

The whole calculation assumes an extra job is worth its gross profit to you. That is only true if you have the capacity to do it. If you are already booked six weeks out and turning enquiries down, an extra enquiry is worth close to nothing — or less than nothing, if answering it costs you time you do not have.

For a business at capacity, the website's job is different and the calculation should be too. It is not there to bring more work; it is there to bring better work — to let you filter, to raise your prices without losing the enquiries that matter, and to make the case for a rate that people accept before they call.

If that is your situation, run this calculator with a higher average job value rather than more jobs. The website that lets you charge fifteen percent more on the same volume has a far better return than the one that brings you jobs you cannot fit in, and it is a genuinely different design brief: proof, specificity, and the confidence to state a price.