by Austin LeClear
on March 16, 2026
TLDR: Don’t switch from a maximize conversions to a target CPA (tCPA) bid strategy on Google Ads until you have at least 30 conversions in the last 30 days. When you do switch, set your target CPA above your current average — not below it. In this post, we’ll explore exactly how to do it without tanking your Google Ads campaign.
Prefer video? Check out When to Switch from Max Conv. to tCPA (Most Get This Wrong) on YouTube:
Still with us? Good, let’s dive in.
If you’ve been running Google Ads for any amount of time, you’ve probably been told the same thing: start with a maximize conversions bid strategy, collect data, then move to target CPA. Simple enough advice — but the execution is where most advertisers blow it.
Whether you’re managing a brand new campaign or testing a new service type inside an existing account, the question always comes up: when is the right time to switch to a target CPA bid strategy? And more importantly, how do you make that switch without completely killing your campaign performance?
Let’s break it down.
The 30/30 Rule: Your Green Light for Target CPA Bidding
Before you even think about switching your bid strategy, there’s one number you need to hit: 30 conversions in a 30-day period.
This isn’t arbitrary. It comes down to how smart bidding actually works under the hood.
When you’re running a maximize conversions campaign, Google’s only job is to spend your daily budget and get you as many conversions as possible. It doesn’t care about efficiency. It doesn’t think about your cost per acquisition. It’s just saying, “Give me the ad spend and I’ll go find conversions.” No ceiling, no floor — just volume.
Target CPA bidding is a completely different animal. When you use target CPA, you’re essentially giving Google Ads a ceiling. You’re saying, “I want as many conversions as possible, but I need to average a certain cost per action over time.” Google then uses your historical data and conversion history to figure out which auctions it can enter and still hit that average target cost.
Here’s the problem: if you switch to target CPA bid strategy without sufficient conversion volume, Google has nothing to work with. It doesn’t know what a converter looks like. It can’t figure out which auctions to enter to average out your target cost per acquisition. So what does it do? It starts to suffocate.
The campaign trickles impressions. Clicks slow down. Your daily budget stops spending fully. And you’re left wondering what went wrong.
That’s what happens when people jump to target CPA too early — usually after five or ten conversions — and then set an aggressive CPA target the campaign has never even hit before. Google can’t manufacture results out of thin air just because that’s the number you want.
That’s why it is so important to get as many conversions as possible inside your Google Ads campaign before you use target CPA. 30 conversions in 30 days is your baseline. At 50+, you can move with real confidence. The more conversion data you have, the smoother the transition to a target CPA strategy.
What’s Actually Happening: Maximize Conversions vs Target CPA
Think about it this way. Imagine there are 12 auctions available for the keywords in your Search campaigns. On maximize conversions, Google enters all 12 — as long as your budget allows. It doesn’t care if some of those auctions are wildly expensive.
Your CPA can swing 3–4x your ideal target and the algorithm won’t flinch. That’s the trade-off with maximize conversions bidding: maximum reach, zero efficiency control.
Switch to a target CPA bid strategy, and suddenly Google is filtering. It looks at each available auction and asks, “Can I enter this and still average out the target CPA my advertiser needs?” If the answer is no, it skips it entirely. Out of those same 12 auctions, it might only enter six. Fewer auctions, yes — but you get a stabilized, controlled average CPA over time.
That ceiling is both the power and the limitation of target CPA strategy. It protects your efficiency but restricts your reach in Google Ads. Which is exactly why it only works well when there’s enough conversion data behind it to make smart decisions.
How to Make the Switch (Without Wrecking Everything)
Here’s where many advertisers get into trouble. They see they’re averaging a $307 CPA on maximize conversions, decide they want a $250 CPA, and immediately set their target CPA to $250. Volume dies overnight.
Don’t do that.
When you set a target CPA, you’re telling Google’s automated bidding what ceiling to work within. If your actual CPA over the last 30 days has been $307 and you immediately drop to $250, you’re wiping out most of the auctions Google has been entering to get you those results. You’re not walking toward efficiency — you’re just destroying volume.
The right move is to set your initial target CPA slightly above where you’re currently performing. For example, if your average CPA is $307, do not set your target below $307.
Instead, in this case you might consider setting your target at $320 when you first switch. This gives Google breathing room to transition from “spend everything” mode into “optimize for a target” mode without sending the campaign into a learning phase spiral.
Here’s our thinking, step-by-step:
- Confirm you have 30+ conversions in the last 30 days in your existing campaign
- Go to campaign settings in the Google Ads interface and change your bid strategy
- Select “Target CPA” and set it slightly above your current average CPA (roughly 5–10% above)
- Let it run for at least a week and monitor for consistency in conversion volume and spend
- Stair-step your CPA target down gradually over time until you reach your actual goal
The stair-step approach is everything. You’re not going to get from $307 to $250 overnight, and you shouldn’t try to. Make small adjustments, wait for the campaign to stabilize, then move again. Slow and steady wins here.
Final Thoughts
- Don’t switch to a target CPA bid strategy until you have at least 30 conversions in 30 days
- More is better — 50+ conversions makes the transition significantly smoother
- Target CPA creates a ceiling — Google skips expensive auctions to hit your average cost per action
- Never set your initial target CPA below your current average CPA — you’ll kill volume instantly
- Stair-step down over time to reach your actual efficiency goal
Get this right and you’ll have a smart bidding strategy that actually works. Get it wrong and you’ll be staring at a suffocated campaign wondering why it stopped spending.
Now go check your conversion data.
