Google Ads

Spend added up day by day, this month and the same month a year earlier — the figures the chart is drawn from.

• What a lead is worth. Since 18 September 2026 one Google conversion is one lead sent after an ad click. Its worth is the margin (invoice less costs, from the ledger) of the bookings those leads went on to make, divided by the leads — from the ad-only /lp- pages, over the twelve months that end two months back so the leads have had time to book.
• Target CPA. That worth, times the share chosen above. At 100% the ads break even on the bookings' margin; below it they leave the rest as profit.
• What a lead costs now. The last three complete months' spend over Google's conversions — with the months before the fix corrected by how many conversions Google counted for each real lead on the /lp- pages, since the old tag counted reloads and repeat visits too.
• Steps. Google's bidding follows a target that moves at most about 15% at a time, two weeks apart; a bigger jump restarts its learning and can stop a campaign spending for days. A campaign with under 15 conversions a month is too thin for a target of its own — share one across campaigns (a portfolio target) or leave it on Maximize conversions.
• Budget. Last year's same month, scaled by how this year's spend is running against last year's, plus the searches the Search campaigns missed for want of budget last month — bought at a fifth above today's cost, and only while a lead still comes in under the target. Leads, bookings and margin follow from what a lead costs in that month (last year's pattern: Q4 is dearer) and what one has been worth. It is a projection from last year and today, not a forecast.