Google Ads budget calculator

This calculator works backwards from the number of enquiries you want each month to the ad spend that number implies. It suits a UK business planning its first Google Ads campaign, or one checking whether its current budget can realistically produce the leads it expects. The figures already in the form are example values in pounds, not UK benchmarks; replace them with your own.

How the budget is worked out

1. Clicks needed = leads wanted ÷ conversion rate. If 5% of visitors enquire and you want 30 leads, you need 600 clicks.
2. Ad spend = clicks needed × average cost per click. At £2.50 a click, 600 clicks cost £1,500.
3. Cost per lead = ad spend ÷ leads. In this example, £50 a lead.

Any management fee is added on top to give the total monthly cost of running the ads. The tool rounds money to whole pounds and clicks up to the next whole click.

Where to find each figure

Conversion rate

This is the share of people who click an ad and then enquire, call or book. If you already run ads, take it from the account, but only if conversion tracking records genuine enquiries rather than page views or button clicks. If you have never run ads, your website’s current conversion rate from Google Analytics is a reasonable starting point, though paid visitors who searched for exactly what you sell can behave quite differently. Run the calculator at a few rates, say 2%, 4% and 6%, and plan around the cautious one.

Cost per click

Your cost per click depends on your keywords, your location, how many competitors bid and the quality of your ads. Google’s Keyword Planner shows a low and high top-of-page bid range for each keyword in a UK location you choose; the high end is the safer figure to plan with. If you have an account history, use the average cost per click for the campaigns you intend to keep. Published averages are a weak substitute for your own keywords; my guide to judging UK cost per click and cost per lead benchmarks explains why, and where to find UK cost signals before you spend anything.

Lead target

Base this on what sales can handle and what you need to close. If one in four leads becomes a customer and you want eight new customers a month, you need 32 leads.

Turning the monthly figure into a daily budget

Google Ads asks for an average daily budget, not a monthly one. Divide your monthly ad spend by 30.4, the figure Google uses for an average month. On a busy day Google may spend up to twice that daily amount, but over a calendar month it should not charge more than the daily budget multiplied by 30.4, so the monthly total stays where you planned it.

Ad spend in this calculator is the cost of clicks before any VAT. Whether VAT appears on your Google Ads invoices, and whether you can reclaim it, depends on your VAT registration, so check this with your accountant before you set the budget.

What the result does not tell you

• Whether the leads are any good. A budget that buys 30 enquiries is wasted if most come from the wrong area or want a service you do not offer. Search terms and negative keywords decide that, not the budget.
• Whether the leads pay. Cost per lead only matters against what a customer is worth. Put the spend into the ROAS and ROI calculator to see if the ads would cover their own cost.
• Whether the budget is enough to compete. If the result is too small to show your ads for much of the day, Google reports the shortfall as impression share lost to budget. Spreading a small budget across many keywords makes this worse; fewer, tighter keywords usually make a small budget go further.
• How long it takes to settle. New campaigns rarely hit the planned cost per click and conversion rate in the first weeks. Treat month one as the period that gives you real figures to put back into this calculator.
• Whether automated bidding has enough to learn from. The note under the result uses a fixed monthly spend as a rough cut-off for this. What Google’s automated bidding actually depends on is how many conversions the account records, not how much it spends, so check your own conversion volume and treat the note as a prompt to look, not a rule.

The quickest way to change the answer without spending more is usually the conversion rate. Moving it from 4% to 5% cuts the clicks you need by a fifth, and that comes from the page people land on: whether it matches the ad, loads quickly on a phone and makes enquiring easy. The landing page checklist goes through those points in order.

Next step

If the budget looks affordable, the next questions are which keywords to start with and how to structure the campaigns so the money goes to searches that turn into enquiries. That is the work I do in ongoing PPC management. If the figure looks too high, or you are not sure your inputs are right, send me your numbers and I will tell you which one I would question first.