Targets from unit economics
Tell us your unit economics and we'll work out your targets.
The gap
In many audits, the target CPA comes from a feeling, a previous agency, or the month in which someone set it. None of those connects the target to what a customer is worth.
Google defines target CPA as an average, not a per-conversion ceiling. Individual conversions can cost more or less. The quality problem is separate: if a booked job, a weak form and a duration-only call all sit in the same bidding goal as equal conversions, the bidder is not receiving the later business distinction.
Meanwhile the account may already assign a completed job more value than a form fill. Target CPA and Maximise conversions optimise conversion count rather than configured monetary value, so those values are not the bidding objective. A value-based strategy can use the distinction if the values and selected goals are credible.
What we do
We start with four numbers from you. What a lead of each type is worth, roughly. What proportion of each type closes. What the average job pays. What you can spend.
From that we derive an expected contribution for each conversion action. If a completed job contributes £200, 90 per cent of bookings complete, forms close at 20 per cent and qualified calls close at 50 per cent, the expected values are £36 for a form and £90 for a qualified call. Those values can support Maximise conversion value or a target ROAS where that objective and the data volume are appropriate.
Ecommerce uses a different unit
Lead generation values an enquiry from what happens later in the sales process. Ecommerce starts with transactions and order lines, then keeps three commercial distinctions visible:
- Brand demand versus non-brand acquisition.
- New customers versus returning customers.
- Products or product groups with different contribution after discounts, refunds and supplied costs.
Those dimensions are worked out separately before deciding whether they need separate campaigns, custom labels, product groups, customer lifecycle settings or value rules. The account structure follows the economics and available volume, not the other way round.
See ecommerce Google Ads management for the operating model and the client-owned data warehouse for the transaction and order-line reference layer.
The rule
Google began changing delivery for affected limited-by-budget target strategies on 17 August 2026. Its documentation says those campaigns will perform more consistently toward their stated target. The following is Fire Pixel's decision rule, not a universal Google instruction.
If the budget genuinely binds and the business objective is maximum conversion value from that fixed spend, we normally test Maximise conversion value without a target. Google lists this as an option for capturing the highest conversion volume or value within a set budget. It removes an efficiency constraint; it does not guarantee a better CPA or ROAS.
A target CPA or ROAS earns its place when efficiency is the real constraint: for example, when the advertiser will buy additional volume only at a given return, or when cashflow or a contract makes the limit non-negotiable. The number should come from contribution and risk tolerance rather than a trailing platform average alone.
Where the bidding strategy supports a portfolio bid limit we keep one as an explicit backstop, checked in the weekly loop, because a backstop that starts binding has become a second constraint.
Where there is a call threshold, it gets raised at the same time. Moving to value bidding while a thirty second call still carries £80 tells Google to buy more thirty second calls.
What you get
A one-page target derivation you can read and argue with. The conversion value schema. The bidding setup. A quarterly review where the numbers are re-derived from what the CRM says happened.
Free tools
Use the Conversion Value Schema Builder to turn close rates, completion rates and contribution into a first value model. The Budget / Target Constraint Checker then identifies the account evidence needed to distinguish a budget constraint from a CPA or ROAS constraint.
Sources checked
- Google Ads: about target CPA bidding
- Google Ads: August 2026 target rollout
- Google Ads: options for affected campaigns
Related: Your target CPA is a made-up number · Target CPA is an average, not a ceiling · Budget is the limiter
FAQ
We have always used target CPA. Why change?
Target CPA optimises the conversion actions included in its goal to an average acquisition cost. If those actions represent materially different business outcomes but are counted equally, use better goals or value bidding. If they are genuinely equivalent, target CPA may remain appropriate.
Won't switching bidding cause a dip?
It can. A changed goal or bid strategy needs time and enough conversion data to settle, and no honest adviser can promise the direction of the short-term result. We stage the change and judge it after at least one or two conversion cycles.
What if I don't know my numbers?
Then we work them out from the CRM together. Most businesses know more than they think once someone asks the right four questions.