How do I filter by source and medium in Google Analytics 4?

Filtering by source and medium lets you isolate specific traffic channels — like organic search, email campaigns, or paid social — so you can measure their performance independently. This is one of the most common segmentation tasks in Google Analytics 4.

What Are Source and Medium?

In GA4, source identifies where traffic came from (e.g., google, newsletter, facebook) and medium describes the channel type (e.g., organic, email, cpc). Together they form source / medium pairs like google / organic or email / newsletter.

GA4 exposes two sets of these dimensions:

sessionSource / sessionMedium — the source that brought the user into this specific session. Used in Traffic Acquisition reports.
firstUserSource / firstUserMedium — the source that originally acquired the user. Used in User Acquisition reports.

Step-by-Step Guide

Step 1: Open the Traffic Acquisition Report

In GA4, go to Reports → Acquisition → Traffic acquisition.

This report shows sessions broken down by session default channel group. The table includes columns for sessions, users, engagement rate, and conversions.

Step 2: Add a Source / Medium Filter

Click the search/filter bar above the data table (the magnifying glass icon), or use the "Add filter" option (pencil icon in the top right of the report).

Select the dimension Session source / medium from the dropdown.

Step 3: Enter Your Filter Value

Type the source/medium combination you want to isolate:

google / organic — Google search traffic
(direct) / (none) — direct visits with no referral
email / newsletter — email campaign traffic
facebook / cpc — paid Facebook ads

Click Apply. The report now shows only sessions matching that source/medium.

Step 4: Adjust Metrics (Optional)

Use the "Customize report" option (pencil icon) to add or remove columns. For source/medium analysis, useful additions include:

Conversions (by event)
Total revenue
Average engagement time

Analyzing Multiple Sources at Once

To compare several sources side-by-side without filtering, remove any active filters and use "Session source / medium" as your primary dimension by clicking the dimension dropdown in the table header.

For more complex segmentation (e.g., all paid channels combined, or a specific set of campaigns), use Explore → Free Form:

Go to Explore in the left sidebar
Create a new Free Form exploration
Add sessionSourceMedium as a dimension
Add your chosen metrics
Use the Filters panel to include or exclude specific source/medium values

What to Look For

High sessions, low engagement rate — traffic is arriving but not engaging. Check whether the landing page matches what that source promised.
Low session volume, high conversion rate — a small but highly qualified channel. Worth investing more in.
(direct) / (none) is very large — often a sign of untagged email links or mobile app traffic being misclassified.

Common Issues

Campaign traffic showing as (direct) — UTM parameters on your campaign URLs are missing or being stripped. Check your links for utm_source and utm_medium tags.
Traffic split between multiple source/medium values for the same channel — inconsistent UTM naming (e.g., Email vs email vs newsletter). Standardize UTM conventions across your team.

Using Sequel

Connect your Google Analytics account to Sequel and ask:

"Show me sessions and conversions from paid social last month"

"Compare organic search vs email traffic for the last 90 days"

"Which source/medium drove the most revenue this quarter?"

Sequel queries the GA4 API directly and handles the dimension filtering for you — no report configuration or Explorations setup needed.