Split testing
Split testing for ads with a verdict from your own figures
Adrails runs two to four versions of an ad set or an ad that differ in one variable, follows them from the launch and names a winner once the difference is reliable. Creating the variants, launching and ending happen in Adrails, and nothing spends before you launch.
Reviewed Oct 4, 2026
Two kinds of test
What each kind starts from, and what can vary
One variable changes per test. The rest of the ad set or ad stays as it runs.
| Test | Meta split test | Tracked by Adrails |
|---|---|---|
| Starts from | A Meta ad set | An ad, on Meta or Google Ads |
| How it runs | Meta divides the audience between the ad sets, so nobody sees two versions, and each ad set spends its own budget | The ads run side by side in the same ad set. The audience is not split and the budget is not divided: the platform decides who sees which ad |
| Measured by | Meta's study and Adrails | Adrails, from the launch |
| Needs | A campaign on ad set budget without budget sharing, an ad set with its own daily budget, and an account in a Meta business portfolio | An ad Adrails can copy |
| Can vary | Audience (age, gender, countries), placements, or bidding (bid strategy and its amount or minimum ROAS) | Ad text or creative on a Meta ad with one image or video; headlines and descriptions on a Google responsive search ad; creative on a Google responsive display or Demand Gen image ad |
From the split tests guide in the Adrails docs. Carousels, dynamic creative and existing posts cannot be tested, and a Google ad group is tested through the ads inside it.
Product view
Set up the test where the campaign lives
Pick the ad set or ad to test from Campaigns, read the variants side by side in the campaign detail, and end the test from the same screen.
Four steps
Create, launch, follow, end
Each step is one page in Adrails. Two of them, the launch and the end, are proposals you apply in Priorities on Home.
01
Create the variants
Open an ad set or an ad in Campaigns and choose Split test. Name it, choose what varies and whether it is decided on CPA or conversion rate, set 4 to 30 days and fill in B to D. The variants are created on the platform, paused.
02
Launch from Priorities
Adrails checks that the campaign and ad set are active and the variants are ready, then the launch waits in Priorities on Home as one proposal. Applying it switches the variants on and, for a Meta split test, creates Meta's study.
03
Follow the verdict
The test's page shows the day it is on, the conversions it has and how many more it needs, and each variant's figures. Adrails reads running tests about once an hour and names a winner at 95% confidence.
04
End it: pause the others
Once a winner is found, End test prepares a pause for each losing variant, waiting in Priorities. Applying one also stops Meta's study. A test that reaches its end date without a reliable leader is marked Ended and nothing is paused.
Go further
Read more
- Split tests in the docsEvery step, from Create variants to End test, and what to watch for.
- Compare in the docsThe same verdict on any two to four campaigns, ad sets or ads.
- CBO vs ABOWhen ad set budgets beat a campaign budget, with a decision table for testing and scaling.
- Creative fatigue monitoringSpot the creative to test next from its own decline, week against week.
FAQ
Common questions
Can I run a Facebook ads split test from Adrails?
Yes. From a Meta ad set, a Meta split test divides the audience between the ad sets so nobody sees two versions, and Adrails creates Meta's study when you launch. The campaign must use ad set budget without budget sharing, the ad set needs its own daily budget, and the account must belong to a Meta business portfolio.
How many conversions does a split test need before a winner is named?
At least 10 per variant. The leader is then tested against every other variant at 95% confidence, corrected for the number of variants, and until then the test's page says how many more conversions it needs.
Can I A/B test Google Ads in Adrails?
Yes, on the ads: the headlines and descriptions of a responsive search ad, or the creative of a responsive display or Demand Gen image ad, tracked by Adrails from the launch. Ad groups cannot be tested, and new Google Ads connections open once Google finishes verifying Adrails, so a new workspace tests on Meta Ads first.
What happens when a test ends without a winner?
Its status becomes Ended and nothing is paused. The test appears in Priorities on Home with an Open test button, and you decide what to do with the variants yourself.
Can I test a carousel or a dynamic creative ad?
No. Carousels, dynamic creative and existing posts cannot be tested, and a Meta ad's creative can vary only when the ad has one image or video. Ad text can vary on any Meta ad that can be tested.
How long does a split test run?
From 4 to 30 days, 14 by default, counted from the launch. Adrails checks running tests about once an hour and names the winner as soon as the leader is reliable, before the end date if the figures allow it.