How to Choose Between tROAS and tCPA in Google Ads
A deep dive into Target ROAS and Target CPA strategies, LTV calculations, conversion value models, and Google Ads auction mechanics — using a real internet provider example.
⚖️ tROAS vs tCPA: Which Strategy to Choose?
You pass dynamic conversion value (LTV × conversion rate). The algorithm optimizes for revenue/spend ratio.
- Best when tariffs have different values
- Requires setting up dynamic value passing
- More complex setup, but higher revenue potential
You set a fixed target cost per acquisition. The algorithm optimizes for getting conversions at your target price.
- Best when CPA is predictable and stable
- No need to pass conversion values
- Simpler setup, easier to control budget
🎯 The Problem: What Lead Value Should You Pass?
When setting up Target ROAS in Google Ads, the key question is what conversion value to pass when a form is submitted. This determines how the algorithm bids at auction.
Let’s examine an internet provider with three tariff plans:
| Tariff | Connection | Monthly Fee | LTV (24 mo) | Lead Value (×50%) |
|---|---|---|---|---|
| Giga Hryvnia v 2.0 | 750 UAH | 1→275 UAH/mo | 5 706 UAH | 2 853 UAH |
| Easy Start | 250 UAH | 0→275 UAH/mo | 6 025 UAH | 3 012.5 UAH |
| 1000 Mbps — Standard | 250 UAH | 275 UAH/mo | 6 850 UAH | 3 425 UAH |
📊 Three Conversion Value Models
Every form passes the same amount (e.g. 300 UAH). The algorithm sees no difference between tariffs and cannot optimize bids for profitable leads. You lose your most valuable customers.
Passes connection fee + first month. The algorithm sees some difference but underestimates long-term customer value. Tariffs with no connection fee get almost no traffic.
Passes LTV × conversion rate. The algorithm sees the true economic value of each lead and has wide bidding room. Your campaign stays stable even when competition increases.
⚙️ How tROAS Works at Auction: The CPL Formula
Target ROAS uses a simple but critical formula to determine the maximum bid at auction:
CPL = Conversion Value ÷ Target ROASExample: If you pass a lead value of 3,425 UAH (Standard tariff) and set tROAS = 500%, your max CPA at auction = 3,425 ÷ 5 = 685 UAH.
This does not mean you will pay 685 UAH per lead. It means the algorithm can raise the bid up to 685 UAH when it sees a high-probability customer. The actual CPA is usually 2–3 times lower.
🚦 Senior Rule: Adjusting tROAS When Prices Change
If you change lead value by more than 20–30%, you must proportionally adjust the Target ROAS in your campaign settings:
| Scenario | Lead Value | tROAS | CPL | Result |
|---|---|---|---|---|
| 📉 Prices dropped 50% | 1 712 UAH | 500% ❌ (not changed) | 342 UAH | Campaign stops |
| 📈 Prices increased 50% | 4 500 UAH | 500% ❌ (not changed) | 900 UAH | Budget bleed |
| ✅ Correct adjustment | 4 500 UAH | 750% ✅ (raised) | 600 UAH | Stable operation |
💰 How to Choose a Daily Budget for tROAS
Daily budget must be tied to CPA, not to a comfortable amount. The golden rule: budget ≥ 5–10 × CPA.
| Budget/day | Leads/day | Status | Recommendation |
|---|---|---|---|
| 100 UAH | < 1 | 🔴 Critical | Do not run. Budget below CPA |
| 300 UAH | 1–2 | 🟡 Risky | Minimum, but learning is slow |
| 1 000 UAH | 4–6 | 🟢 Optimal | Ideal for launch & learning |
❓ Frequently Asked Questions
🛠 Technical Setup: DataLayer + GTM
To pass dynamic conversion values to Google Ads, set up a DataLayer on your site. When a form is successfully submitted, the site should push an event:
window.dataLayer = window.dataLayer || [];
window.dataLayer.push({
'event': 'lead_submission',
'tariff_name': 'Standart_1000',
'value': 3425,
'currency': 'UAH'
});In Google Ads: create a «Form submission» conversion, select «Use different values for each conversion».
In GTM: link the value variable from dataLayer and pass it to your Google Ads conversion tag.