CPA formula – how it works

CPA measures how much you pay for a single conversion. The formula is straightforward:

CPA = Advertising cost ÷ Conversions

Lower CPA means you are generating conversions more efficiently. When used as a segmentation signal, CPA helps identify which products deserve more budget — and which ones should be limited or excluded.

How to use CPA campaigns in practice

A CPA structure groups products by conversion efficiency. Each tier gets a different budget and bidding intensity based on how well it performs.

Before you segment:

• Make sure products have sufficient data (clicks or conversions).
• Exclude untested products, those belong in a testing or new product campaign.
• Define clear CPA ranges based on your account average.

Core CPA segments

TOP products

These are your most efficient converters.

Typical criteria:

• Low CPA (e.g. below 200 CZK)
• High ROAS (e.g. above 500%)
• Stable conversion volume

These products should receive the largest share of budget and the most aggressive scaling.

MID products

Products close to the account average with optimization potential.

Typical criteria:

• Medium CPA range
• Average or slightly above-average ROAS
• Inconsistent but promising performance

MID products are ideal for controlled testing and gradual improvement.

LOSER products

Products that hurt overall performance.

Typical criteria:

• High CPA
• Low ROAS
• Poor efficiency despite sufficient traffic

These products should be heavily limited, paused, or excluded for at least 30 days.

Campaign structure options

2-campaign structure

• Low CPA campaign: TOP products with aggressive tCPA targets and most of the budget
• High CPA campaign: Weaker products with limited budgets to capture residual demand

3-campaign structure

• TOP CPA campaign: Best-performing products
• MID CPA campaign: Products under optimization
• LOSER CPA campaign: Minimal budget or fully excluded

4-campaign structure with testing pool

• TOP, MID, and LOSER campaigns
• Testing campaign: Products with insufficient data, using Maximize Conversions and a small daily budget

This prevents untested products from harming proven performers.

Bidding strategy and goals

The primary bidding strategy is Target CPA (tCPA).

For accounts where revenue quality also matters, CPA segmentation can be combined with ROAS thresholds to avoid scaling low-value conversions.

The main objective is simple:

• Push spend toward low-CPA products
• Improve or remove high-CPA products

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