I’ve spent $200M+ on Google Ads, and Target CPA (tCPA) is still one of the most misused bidding strategies out there. Turn it on too early and you stall. Set the target too aggressively and you lose 40% of your traffic overnight.
Here’s the exact playbook we use at TNT Growth to max out tCPA campaigns — from when to flip it on, to how to set the target, to the down-funnel signals that make it actually work.
1. Check minimum requirements
Target CPA needs conversion volume to learn. If you’re under these thresholds every 30 days, don’t turn it on — stay on Maximize Conversions until you hit them:
- Search = 15
- Display = 15
- App = 10 (but 300+ if you want stability)
- Demand Gen = ~30
- Performance Max = ~30
One important caveat: these numbers need to come from across your account, not all concentrated in Branded keywords. Branded conversions train the algorithm on the wrong audience.
2. Set tCPA around historical performance
Pull your CPA column over the last 4 weeks and exclude the last 3-7 days to account for conversion delay (if you experience that). Then set your target at or above that number.
Do not try to set tCPA below historical just yet. I’ve seen accounts lose 40%+ traffic overnight from doing that. It kills your volume and hands share right back to your competitors.
3. Train on down-funnel conversions
This is where most accounts leave performance on the table. Google optimizes for whatever event you feed it. If you feed it form fills, you’ll get form fills — not customers.
- Upload offline conversions from your CRM (MQL, SQL, Closed Deal) so Google optimizes for buyers, not lead forms.
- Push bad leads back within 24 hours so the algorithm stops finding lookalikes of junk.
- Move your primary conversion action as far down-funnel as possible while still holding 30-50+ conversions/month.
The deeper the event Google optimizes for, the better the lead quality it hunts for.
4. Watch Search Lost IS (Budget)
Search Lost IS (Budget) tells you whether your tCPA is actually in line with the market:
- If Search Lost IS (Budget) is >0%, your tCPA might be too low. Raise it until lost-to-budget hits zero — or increase your budgets if you’re already hitting your desired CPA.
- Keeping this metric pinned near zero keeps your CPCs efficient throughout the day instead of spiking when budget runs thin.
5. Make gradual adjustments
Once the campaign is stable, you steer it in 5-10% increments:
- Want more volume? Raise tCPA in 5-10% increments.
- Want more efficiency? Lower tCPA in 5-10% increments.
- Wait 1-2 conversion cycles after any change before judging performance. Pull the lever again too fast and you’re reacting to noise, not signal.
The tCPA cheatsheet
- Turn on tCPA at the right time — not before you hit conversion minimums.
- Set tCPA around historical performance, not wishful thinking.
- Watch Search Lost IS (Budget) to know when to adjust tCPA.
- Make gradual 5-10% changes and wait 1-2 conversion cycles before judging.
Nail these five steps and tCPA stops being a volatile lever and starts compounding. What’s your tCPA playbook look like?