What Is Target CPA?
Target CPA is a Smart Bidding strategy in Google Ads that tells the system: "Get me as many conversions as possible, but try to keep each conversion below this rand amount." You set the target, and Google's machine learning handles every bid, raising it for high-probability auctions and lowering it for lower-probability ones, all with the goal of hitting your average cost per acquisition across all conversions.
The word "acquisition" in CPA is flexible. For a law firm in Johannesburg, an acquisition might be a completed contact form. For an e-commerce store selling outdoor gear, it might be a completed purchase. For a Cape Town hotel, it might be a room booking. Whatever you define as a conversion in your Google Ads account becomes the thing the algorithm tries to generate at or below your target cost.
It is important to understand that Target CPA is an average target, not a hard cap. On any given day, Google may spend R250 on one conversion and R80 on another. What it aims for is an average across all conversions that lands near or below your stated target. If you set a Target CPA of R150, expect individual conversions to vary above and below that figure, but the campaign average should trend towards it over time.
Target CPA works best when an account has a consistent history of conversions. Google recommends at least 30 to 50 conversions in the past 30 days before activating this strategy. Without that foundation, the algorithm is essentially guessing and will often overspend on poor-quality traffic while missing the auctions that would actually convert. Starting with Maximise Conversions first builds up this data before introducing a cost constraint.
Target CPA In Practice
A Durban-based accounting firm wanted to grow its client base through Google Ads. The account manager reviewed three months of historical data and found their average cost per lead was R420. They activated Target CPA at R450 (slightly above average to give the algorithm room) for campaigns targeting "tax accountant Durban" and "small business accounting services KZN". Within six weeks, the campaign was generating 35% more leads per month at an average actual CPA of R390, comfortably below target.
A common pitfall for South African businesses is setting an overly aggressive Target CPA from day one. If the historical average cost per lead is R500 but the Target CPA is set at R200, the algorithm will underdeliver because it cannot find enough auctions at that price point. The result is a campaign that spends very little and generates few conversions. Setting the target close to historical performance, then gradually reducing it once the strategy is stable, produces far better outcomes.
How Target CPA bidding works
Target CPA is a Smart Bidding strategy that sets bids to win as many conversions as possible at around a cost per acquisition you specify. You tell Google the average you are willing to pay for a conversion, and it bids higher on auctions predicted to convert affordably and lower on those unlikely to, aiming for the target across the campaign rather than on every single conversion. Because it counts conversions equally, it suits lead generation and other cases where each conversion has similar value. It relies on conversion tracking and enough history to predict well; set on too little data, or with an unrealistically low target, it can suppress volume as it struggles to find conversions at the price.
When to use Target CPA
Target CPA fits campaigns focused on a stable, predictable cost per conversion where conversions are worth roughly the same, classically lead generation. It works best once a campaign has accumulated reliable conversion data, so a new campaign often starts on Maximise Conversions to gather history before switching. Set the target from your real, achievable cost per acquisition, informed by past performance, rather than an aspirational number, because a target far below what the market allows will starve the campaign of traffic. It is less suitable where conversion values vary, where Target ROAS fits better. As with all automated bidding, accurate conversion tracking is the precondition, since the strategy optimises entirely towards the conversions you report.
FAQ
How do I set the right Target CPA?
Start by reviewing your historical average cost per conversion from the last 30 to 90 days. Set your initial Target CPA close to that historical average, not an aspirational figure. Once the strategy has gathered data over two to four weeks, you can gradually lower the target by 10 to 15 percent at a time and monitor for volume drops.
Why is my Target CPA campaign spending below budget?
If your Target CPA is set too low relative to the actual cost of acquiring a conversion, Google's algorithm will limit bidding to auctions it believes can hit that target, reducing total spend and conversion volume. Raising the Target CPA slightly often restores budget pacing and increases overall conversions while keeping cost per lead reasonable.
What is the difference between Target CPA and Maximise Conversions?
Maximise Conversions spends the full budget to win as many conversions as possible without a cost target, so cost per conversion can vary. Target CPA aims for a specific average cost per conversion. Use Maximise Conversions to gather data or spend a set budget, and Target CPA to hold a defined efficiency.
Does Target CPA guarantee my cost per acquisition?
No. It aims for the target on average across the campaign, not on every conversion, so actual costs vary around it and can exceed it, especially during learning or if the target is unrealistic. It is a goal the system optimises towards, not a fixed price.