YouTube Thumbnail Size, Rules and Tips to Get More Clicks (2026)

You spend hours on a video, but people scroll past it. Very often the problem is the thumbnail. It is too busy, the text is too small to read on a phone, or it simply does not look worth a click.

This guide covers the YouTube thumbnail size and rules from YouTube's own help pages, then shows you a simple way to design thumbnails that get clicks without being misleading.

What is the correct YouTube thumbnail size?

YouTube's help page Add custom thumbnails lists these requirements. They can change, so check that page if an upload fails.

Why can't I add a custom thumbnail on YouTube?

The most common reason is that your account is not verified. YouTube says you can upload your own thumbnail "if your account is verified". Verification is free and uses your phone number at youtube.com/verify.

Other reasons from YouTube's help page:

• Daily limit reached: if you see "Daily custom thumbnail limit reached", wait 24 hours. Limits depend on your country and channel history.
• Strikes: copyright or Community Guidelines strikes can affect your thumbnail access.
• Shorts on mobile: custom thumbnails for Shorts can currently be added only in YouTube Studio on a computer.
• Wrong file: the image is too large, too small, or not JPG/PNG.

If you are not sure what your channel can use, our guide on unlocking YouTube intermediate and advanced features shows where to check feature eligibility.

How to add a custom thumbnail to a YouTube video

On a computer (normal video)

1. Sign in to YouTube Studio.
2. Click Content in the left menu.
3. Click the video you want to edit.
4. Under Thumbnail, click Upload file and choose your image. You can also click Get suggestions to see thumbnail ideas.
5. Click Save.

On a computer (Shorts)

1. In YouTube Studio, go to Content and open the Shorts tab.
2. Open the Short and go to its details.
3. Under Thumbnail, click Upload file and pick a 9:16 image.
4. Click Save.

YouTube thumbnail rules you must follow

Thumbnails must follow YouTube's Community Guidelines and its thumbnails policy. In simple words, do not use:

• Nudity, sexual content or sexually suggestive images.
• Gore, violence or vulgar language.
• Hate speech or harmful and dangerous content.
• Someone else's face, logo or channel branding in a way that suggests they made or approve your video.
• Images that promise something that is not in the video. YouTube calls this a misleading thumbnail.

YouTube's policy says a first problem usually gets a warning. Repeat problems can lead to strikes, and serious cases can end a channel. A clickbait thumbnail is never worth that risk.

How to make a YouTube thumbnail that gets clicks (step by step)

You do not need expensive software. A free design app on your phone or computer is enough. Follow these steps.

Step 1: Decide the one promise

Ask: "What will the viewer get from this video?" Write it in 2-4 words. For example, "AdSense Approved?", "Fix No Views" or "Phone Setup". This is your thumbnail text. It should add to the title, not repeat it word for word.

Step 2: Pick one main picture

Use one clear subject: your face with a real expression, the product, or the result screen. Many small objects make the thumbnail look like noise when it is shown at a small size.

Step 3: Use big text and strong contrast

• Use a thick, simple font.
• Keep text large enough to read on a small phone screen.
• Put light text on a dark area, or dark text on a light area.
• Add a thin outline or shadow so text stands out from the background.

Step 4: Leave the bottom-right corner clear

YouTube shows the video length in the bottom-right corner of thumbnails. Do not put your key text there.

Step 5: Test at small size

Zoom out until the thumbnail is about the size of a phone search result. Can you still read the words and see the face? If not, remove something.

Step 6: Keep a channel style

Use the same two or three colours and one font across videos. Over time, viewers start to recognise your videos in their feed.

Good vs bad thumbnail checklist

Use A/B testing to pick the best thumbnail

YouTube has a built-in test for titles and thumbnails. Its help page A/B test titles & thumbnails says:

• It works only in YouTube Studio on a computer, and advanced features must be on.
• You can test up to 3 titles, 3 thumbnails, or 3 title and thumbnail pairs.
• The option with the highest watch time wins and is shown to everyone.
• Tests should finish within two weeks.
• It is not available for Shorts, scheduled lives, premieres before they become normal videos, made-for-kids videos, mature-audience videos or private videos.

To start, open the video in YouTube Studio, click A/B Testing in the title box or under Thumbnail, choose what to test, upload your options and click Done.

How to know if your thumbnail is working

In YouTube Studio analytics, look at impressions and impressions click-through rate for the video. Compare a video with similar ones on your channel, not with big channels. Our guide on YouTube analytics key metrics explains where to find these numbers.

Remember: a high click rate with very short watch time is a warning sign. It often means the thumbnail promised something the video did not deliver. If your videos are still not getting seen at all, read why YouTube videos get no views and how to fix it.

Common thumbnail mistakes

1. Repeating the full title as thumbnail text.
2. Using tiny fonts that look fine on a laptop but not on a phone.
3. Copying a big creator's design so closely that it looks like their channel.
4. Using red arrows and shocked faces on every video, even calm tutorials.
5. Uploading a 16:9 thumbnail for a vertical Short.

Final word

The right YouTube thumbnail size is the easy part: 16:9, at least 640 pixels wide, JPG or PNG. The real work is making one clear, honest promise that is readable on a phone. Keep it simple, test it at small size, and use A/B testing once your channel has access.

Next step: redo the thumbnail of one older video that has views but a low click rate, and compare the result after a couple of weeks. To learn the full process of growing a channel, see our courses.

Sources: YouTube Help, Add custom thumbnails, Thumbnails policy and A/B test titles & thumbnails.