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Understanding Key Metrics in Google Ads: CPA, CPO, and CPL

Google Ads Guide

Feb 19, 2023

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Clients often ask us about the key metrics used in Google Ads and how they impact the success of their campaigns. Here, we explain the differences between CPA, CPO, and CPL and why they matter.

CPA (Cost Per Action)

What is CPA?

In Google Ads, CPA measures the cost incurred when a user completes a specific action, such as making a purchase or filling out a form. It's a versatile metric that helps businesses understand the cost-effectiveness of their ad spend in driving desired actions.

Why is CPA Important?

  • Budget Optimisation: By focusing on the cost per action, businesses can allocate their budgets more efficiently, ensuring that they spend money on actions that drive value.
  • Campaign Performance: CPA provides a clear picture of how well your ads are performing in terms of generating conversions.

How to Use CPA in Google Ads:

  • Set a target CPA for your campaigns.
  • Utilise automated bidding strategies like Target CPA to optimise for conversions within your desired cost threshold.

CPO (Cost Per Order)

What is CPO?

CPO (Cost Per Order) is a metric that reflects the cost of attracting one order. While not explicitly referred to in Google Ads, CPO allows you to evaluate the performance of the entire sales funnel and understand at what stage customers are being lost. To calculate this metric, you need to know the advertising spend and the number of purchases made.

Why is CPO Important?

  • Sales Funnel Analysis: Provides insights into each stage of the sales process, identifying where potential customers drop off.
  • Actual Sales Value: Unlike metrics that focus solely on traffic or impressions, CPO considers the actual sales generated, making it superior for evaluating campaign effectiveness.
  • Budget Efficiency: Reduces the risk of overspending on ineffective ads, crucial for companies with limited budgets.

How to Measure CPO:

  • Implement conversion tracking to accurately measure the number of purchases.
  • Analyse data to identify stages where improvements can be made to reduce CPO.

CPL (Cost Per Lead)

What is CPL?

CPL measures the cost of acquiring a new lead, such as a potential customer who provides their contact information. This metric is vital for campaigns aimed at generating leads rather than direct sales.

Why is CPL Important?

  • Lead Generation Quality: Helps determine the expense and quality of leads generated.
  • Strategy Refinement: Allows for adjustments in targeting and ad content to improve lead quality and reduce costs.

How to Use CPL in Google Ads:

  • Use lead form extensions to capture leads directly from ads.
  • Regularly assess lead quality and adjust campaigns to enhance effectiveness.

Practical Implementation for Google Ads

To effectively use these metrics in your Google Ads campaigns:

  • Set Clear Goals: Determine the specific actions, orders, or leads you want to measure.
  • Monitor Regularly: Keep an eye on these metrics to track trends and impacts.
  • Optimise Based on Data: Use the insights gained from these metrics to refine your marketing strategies and budget allocations.


Understanding CPA, CPO, and CPL is crucial for running successful Google Ads campaigns. These metrics provide valuable insights that help optimise your ad spend, improve campaign performance, and ensure that your marketing efforts are aligned with your business goals. By focusing on these metrics, you can make data-driven decisions that enhance the effectiveness and efficiency of your promotional activities.

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Author: Ashley Phillips

Head of Strategy

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