Connect Google Ads to Power BI for ROAS

You connect Google Ads to Power BI through one of three routes: a third-party connector, the Google Ads API, or exporting Google Ads and GA4 data into BigQuery and connecting Power BI to that. There is no official Microsoft Google Ads connector. For a ROAS dashboard that blends ad spend with GA4 revenue, the warehouse route gives the cleanest model, because the hard part is reconciling spend and revenue on a common grain rather than the connection itself. This guide covers the methods, how to blend with GA4 and the pitfalls that distort the numbers.

The three ways to connect Google Ads to Power BI

1. Third-party connector. Several vendors publish Google Ads connectors that hand you campaign, ad group and keyword tables ready to model. Quick to stand up, at the cost of a subscription, a fixed schema and dependence on the vendor tracking Google Ads API changes. Good for getting going fast.

2. Google Ads API via Power Query. You can query the Google Ads API directly, but authentication uses OAuth and a developer token, and the reporting structure is non-trivial. This route gives full control but is the most engineering-heavy and fragile to maintain inside Power Query.

3. BigQuery / warehouse-first (recommended for ROAS). Export Google Ads and GA4 data into BigQuery (or another warehouse), join them there, and connect Power BI to the result. This is the natural pattern because GA4 already exports cleanly to BigQuery, so co-locating spend and revenue makes blending straightforward and fast. See our data integration and warehousing approach for how this fits together.

Building a ROAS dashboard

ROAS is revenue divided by ad spend, but a credible dashboard needs both sides aligned. Bring spend from Google Ads and revenue from GA4 (or your order system) into one model sharing a common date and campaign grain, then build ROAS as a DAX measure. Prioritise:

• Spend, impressions, clicks, CTR and CPC from Google Ads.
• Conversions and conversion value from the authoritative revenue source.
• ROAS and cost per acquisition (CPA) as measures, sliceable by campaign, ad group, device and date.
• Trend over time so you spot creative fatigue and budget drift.
• Channel comparison, once you add other paid sources to the same model.

Model this as a star schema with date, campaign and channel dimensions rather than one flat export, so measures stay reusable and fast.

Blending with GA4

Pairing Google Ads spend with GA4 revenue is where most dashboards go wrong, because the two systems count differently. Watch for:

• Attribution model mismatches. Google Ads and GA4 can attribute the same conversion differently. Decide which source is authoritative for revenue and which for spend, and state it on the dashboard.
• Conversion windows. A conversion counted today may relate to a click days earlier, so daily spend and daily revenue do not line up one-to-one. Use rolling windows where appropriate.
• Naming consistency. UTM and campaign naming must match across systems or your joins fragment. Enforce a naming convention.
• Currency and time zone normalisation, as always.

The cleanest fix is to export both into BigQuery, join on a deliberate key, and let Power BI read a reconciled table. Our guide on connecting GA4 to Power BI covers the GA4 export side in detail.

Common pitfalls

Spend without revenue. A connector that pulls only Google Ads gives you cost metrics but no ROAS until you add the revenue side.

Refresh and quota limits. Direct API pulls hit quotas and slow down. A warehouse keeps refreshes predictable.

Double counting across channels. When you add more paid sources, ensure conversions are not attributed twice across overlapping channels.

Getting it done properly

A trustworthy ROAS dashboard depends on disciplined blending of spend and revenue, not just a connector. Our Power BI consultants in the UK build governed marketing models with documented attribution, and engagements usually begin with a fixed-scope Trusted Numbers Review (£2,000–£4,000 as of 2026, confirm current pricing) followed by a scope-locked build (from £6,000, typically £8,000–£14,000, confirm current pricing).

Turn ad spend and GA4 revenue into a ROAS view your marketing team can act on. Book a Trusted Numbers Review and we will map the fastest reliable route from Google Ads to decisions you can trust.