How to Use the YouTube Thumbnail Tester to Boost Views

This post was originally written Dec 08, 2023 and has been updated with newer information.

Choosing the right thumbnail can make or break your video’s success, which is why YouTube offers a built-in thumbnail test that lets creators compare designs using real viewer behavior.

With YouTube’s thumbnail tester, you can upload multiple thumbnails for the same video and let YouTube automatically figure out which one performs best. It’s called Test & Compare, and it’s one of the most effective tools for optimizing click-through rates and watch time.

What Is YouTube Thumbnail A/B Testing?

YouTube’s Test & Compare tool allows creators to upload up to 3 thumbnails per video and run a native A/B test inside YouTube Studio.

Each thumbnail is shown to a portion of your audience, and YouTube tracks which one performs best based on a metric called watch time share. After the test concludes, the highest-performing thumbnail is applied automatically.

Why Upload Multiple Thumbnails on YouTube?

Testing multiple thumbnails helps you:

• Understand what actually resonates with your audience
• Improve your click-through rate (CTR)
• Increase total watch time
• Remove the guesswork from design

The best thumbnails don’t just look good, they drive views and watch time. That’s what this tool helps creators uncover.

How to Use the YouTube Thumbnail Tester

YouTube’s built-in thumbnail tester makes it easy to run a thumbnail test directly inside YouTube Studio.

1. Upload your video as usual in YouTube Studio.
2. When you get to the thumbnail step, choose the “Test & Compare” option.
3. Upload two or three different thumbnails.
4. YouTube will automatically rotate the thumbnails to different viewer groups.
5. After collecting enough data, the platform will set the winning thumbnail for you.

Note: This tool works for long-form videos, completed livestreams, and podcasts. Some content types, such as made-for-kids videos, livestreams, or age-restricted uploads, are not eligible for testing.

Does ‘Test and Compare’ Work for all Content Types?

For now, you can test and compare thumbnails on long-form videos, completed livestreams, and podcasts. Shorts and certain types of content, like those aimed at kids or mature audiences, are excluded from using this tool.

Measuring Performance of YouTube Thumbnail Testing

YouTube uses the metric, “watch time share”, as its benchmark of choice. That’s not to be confused with average view duration, which is the average amount of time viewers spend watching a video.

From a testing perspective, the share of watch time each thumbnail earns is what YouTube describes as watch time share. For example, if you test and compare two thumbnails, thumbnail A might accumulate 60% of the watch time, while thumbnail B collects 40%. In this case, thumbnail A is the winner and most likely to boost your views.

But why is YouTube using watch time to test thumbnail performance instead of clicks? After all, the click-through rate measures how attractive a video is on search pages and other display areas.

It turns out that click appeal isn’t enough. In the YouTube Studio, the platform explains why watch time is a better predictor of satisfaction than clicks, and how thumbnails reinforce that.

“Great thumbnails don’t just get viewers to click,” YouTube states. “They also help viewers understand what the video is about, so that they can make informed decisions about what to watch.”

Real-World Example of YouTube A/B Thumbnail Testing

We ran a YouTube thumbnail A/B testing experiment for this video about new AI developments on YouTube.

Here’s what happened:

• We uploaded three thumbnails.
• One version, a simple image of an AI robot, gradually pulled ahead.
• After eliminating the lowest performer and continuing the test, the robot thumbnail earned a 59.7% share of total watch time.
• After switching to the top performer permanently, the video earned nearly 3x the usual views.

Testing works, especially when you focus on designs that align with the video’s emotion, topic, and audience expectations.

New to A/B Thumbnail Testing? A Word of Advice

YouTube’s thumbnail tester is a major step up when you want to optimize your video’s appeal. At the same time, not everyone has the time or resources to create two or three thumbnails per video. If that’s your situation, do small tests instead of large, time-consuming experiments. Make tiny design shifts, like testing different fonts, colors, or simple backgrounds. Even those small tweaks can make a difference in your viewer’s eyes.

This video has more details and advice, so give it a quick watch to cement your knowledge.

But even without a thumbnail test, are you designing images your viewers can’t resist?

Here are 12 thumbnail styles that people love on YouTube!

Quick Tips for Using YouTube’s Thumbnail Tester

You don’t have to design three completely different thumbnails every time. Try testing small variations:

• Zoomed vs. wide shots
• Text vs. no text
• Warm colors vs. cool tones
• Different facial expressions or emotions

These micro-changes can reveal valuable insights during your thumbnail tests and save time in your creative process.

Want Help Designing Better Thumbnails?

Our AI YouTube Thumbnail Maker helps you create bold, clickable designs in minutes, no graphic design experience required.

And if you need inspiration, check out these 12 high-performing thumbnail styles that consistently grab attention and drive watch time.