The Customize tab is in your blog settings, accessed through the gear icon in the top right of your dashboard

When you log into Tumblr on desktop, look for the gear icon in the top right corner of your screen — it sits next to your profile picture. Click it and select "Settings" from the dropdown menu. On the settings page, you'll see several tabs across the top. The "Customize" tab is where you control how your blog looks to visitors: your theme, colors, fonts, header image, and description.

If you're on mobile, the process is slightly different. Tap the menu icon (three horizontal lines) at the bottom right, then tap your blog name, then tap the gear icon. From there, select "Customize blog" to reach the same customization options.

The Customize tab only appears if you're viewing your own blog's settings. If you're looking at someone else's blog, you won't see this option — you can only customize your own.

Key Takeaways

  • On desktop, click the gear icon in the top right of your dashboard, select Settings, then click the Customize tab.
  • On mobile, tap the menu icon at the bottom, select your blog name, tap the gear icon, and choose Customize blog.
  • The Customize tab controls your blog's appearance: theme, colors, fonts, header image, and blog description.
  • You can only customize your own blog, not blogs you follow or visit.
  • Changes you make in the Customize tab take effect immediately and are visible to anyone who visits your blog.

What you can change in the Customize tab

The Customize tab is divided into sections. At the top, you'll see a preview of how your blog currently looks. Below that are options to change your theme — Tumblr offers several built-in themes, and you can also upload a custom theme if you know HTML and CSS.

You can upload a header image (the banner at the top of your blog), change your blog's title and description, set your blog's accent color, and adjust the background. Some themes let you customize additional elements like sidebar width or post layout. The exact options depend on which theme you've chosen — some themes have more customization options than others.

If you want to use a custom theme, you'll need the theme code. Many Tumblr users share free themes on their blogs or on theme-sharing sites. When you paste the code into the "Edit theme" section, Tumblr will preview it before you save.

How to change your blog's basic information

Your blog title and description appear at the top of your blog and in search results. To change them, scroll down in the Customize tab until you see the fields labeled "Title" and "Description." Type in your new title or description and the changes save automatically.

Your blog description is limited to 160 characters, so keep it brief. This is where you tell visitors what your blog is about — for example, "art and design inspiration" or "my photography." The title is what appears as the main heading on your blog.

Uploading and changing your header image

Your header image is the banner that appears at the very top of your blog. To upload one, look for the "Header" section in the Customize tab and click "Upload image." You can upload a JPG, PNG, or GIF file. Tumblr recommends a width of at least 540 pixels, though larger images will display better on desktop.

If you want to remove your header image, click the image that's currently there and select "Remove." Your blog will display with a plain background instead. You can change your header image as often as you want — each time you upload a new one, it replaces the previous one immediately.

Choosing and customizing a theme

Tumblr's built-in themes are free and ready to use. To switch themes, click "Theme" in the Customize tab. You'll see a gallery of available themes with previews. Click on any theme to see a larger preview, then click "Use this theme" to apply it to your blog.

After you select a theme, you can customize its colors and other settings. Some themes have more options than others — a simple theme might only let you change the accent color, while a more complex theme might let you adjust the sidebar, post width, and font sizes. Experiment with different themes to find one that matches how you want your blog to look.

If you want to use a custom theme that someone else created, you'll need to find the theme code and paste it into the "Edit theme" section. This requires some familiarity with HTML, but many theme creators include instructions. Always preview a custom theme before saving it to make sure it looks the way you want.

Troubleshooting common customization problems

If your changes aren't showing up on your blog, try refreshing the page. Sometimes Tumblr's servers take a moment to update. If you've uploaded a new header image and it's not appearing, clear your browser's cache — your browser may be showing you an old version of the image.

If you've applied a custom theme and it looks broken or displays incorrectly, check that you pasted the entire theme code without accidentally deleting any part of it. If you're not sure whether the code is complete, go back to where you found it and copy it again. If a theme doesn't work after you've double-checked the code, it may not be compatible with your version of Tumblr, and you should try a different theme instead.

If you can't find the Customize tab at all, make sure you're logged in to your own account and viewing your own blog's settings, not someone else's blog. The Customize tab only appears for your own blog.

Frequently Asked Questions

Can I customize my blog on mobile the same way as on desktop?

The options are the same, but the layout is different. On mobile, tap the menu icon, select your blog name, tap the gear icon, and choose Customize blog. You'll see the same customization options, just arranged for a smaller screen.

What happens to my customizations if I change themes?

Some settings carry over when you switch themes — like your header image, title, and description. However, color customizations and other theme-specific settings may reset because each theme has different customization options. You'll need to re-customize those elements for your new theme.

Can I use a theme I found on another website?

Yes, if it's a Tumblr theme. Copy the theme code, go to Customize, click "Edit theme," paste the code into the editor, and preview it before saving. Make sure the theme is actually designed for Tumblr — themes from other platforms won't work.

Is there a limit to how many times I can change my blog's appearance?

No. You can change your theme, header image, colors, and description as many times as you want. Each change takes effect immediately and is visible to anyone who visits your blog.

What if I want to go back to my blog's old appearance?

If you remember which theme you were using, you can reapply it from the theme gallery. If you don't remember, you can browse through the available themes until you find one that looks familiar. Tumblr doesn't keep a history of your previous customizations, so you'll need to recreate them manually if you want to switch back.