The Customize tab is in your Tumblr blog settings, accessed through the gear icon on your dashboard

On Tumblr's web version, the Customize tab lives inside your blog settings. Log in and look for the gear icon in the top right corner of your dashboard — it's next to your profile picture. Click it and select "Settings" from the menu. Once you're in Settings, you'll see several tabs across the top: Blog, Customize, and others depending on your account type. The Customize tab is where you control your blog's appearance, theme, and layout.

If you're on Tumblr's mobile app, the process is slightly different. Tap the person icon at the bottom right to go to your profile, then tap the gear icon in the top right corner of that screen. From there, scroll down until you see "Blog Settings" and tap it. You may need to select your specific blog if you run more than one. The mobile version shows fewer customization options than the web version, so for full control over your blog's look, use a computer or tablet browser.

Key Takeaways

  • The Customize tab is found by clicking the gear icon on your Tumblr dashboard, then selecting Settings.
  • You can change your blog's theme, colors, fonts, and header image from the Customize tab without needing coding knowledge.
  • The mobile app has limited customization options compared to the web version, so use a browser for full control.
  • Any changes you make in Customize are saved automatically and appear on your blog when ready.
  • Tumblr offers both free themes and the option to upload custom HTML if you want more advanced design control.

What you can change in the Customize tab

The Customize tab controls the visual appearance of your blog. You can select a theme from Tumblr's library of free templates, each with its own layout and color scheme. Once you pick a theme, you can modify specific elements: change the background color or upload a background image, adjust the header image that appears at the top of your blog, pick your accent color (the color used for links and highlights), and choose fonts for your title and body text.

Below the basic color and font options, you'll find toggles for showing or hiding certain elements. You can turn off the search bar, hide the description under your blog title, or disable the notes counter that shows how many people have liked or reblogged your posts. These settings let you create a cleaner look if you prefer less visual clutter.

Uploading a custom theme or HTML

If Tumblr's built-in themes don't match what you want, the Customize tab also lets you upload custom HTML. This requires some technical knowledge — you'll need to paste code into a text field. Tumblr has a theme editor that shows you the code structure, and many people share free custom themes on sites like ThemeHunter or directly on Tumblr blogs dedicated to theme design.

Before uploading custom HTML, back up your current theme's code. Click "Edit theme" in the Customize tab, and you'll see the HTML editor. Copy all the code and save it to a text file on your computer. That way, if something goes wrong with the custom theme, you can paste your original code back in. Custom themes can break if they contain errors, so test any new theme on a secondary blog first if you have one.

Privacy and security considerations when customizing

When you upload custom HTML or themes, be cautious about the source. Only use themes from creators you trust. Some malicious code can be hidden in custom themes to track your activity or steal information from visitors to your blog. If you read a theme from a third-party site, read the reviews and check when it was last updated — abandoned themes may contain outdated code that creates security gaps.

Avoid pasting code from sources you can't verify. If someone offers you a "special" theme in a message or comment, ask yourself whether you know who they are and whether their reputation is solid. Tumblr's official theme editor is safe, and themes from the official Tumblr theme directory have been reviewed. When in doubt, stick with those.

Reverting to a default theme if something breaks

If you upload custom HTML and your blog stops displaying correctly, you can revert to a default theme. Go back to the Customize tab, scroll to the theme section, and select one of Tumblr's built-in themes. This will replace your custom code with the default theme code. Your posts and content stay intact — only the visual appearance changes.

If you want to keep your custom theme but fix a specific problem, use your browser's developer tools to inspect what's happening. Right-click on the broken element, select "Inspect" or "Inspect Element," and look at the code. This won't let you edit the theme directly, but it can help you identify which part of the code is causing the issue so you can fix it or ask for help from someone who knows HTML.

Customizing different blogs separately

If you run multiple Tumblr blogs under one account, each blog has its own Customize settings. When you click the gear icon and go to Settings, make sure you're viewing the correct blog — you'll see your blog name at the top of the Settings page. If you have more than one blog, you can switch between them using a dropdown menu. Each blog's theme, colors, and layout are independent, so you can have completely different looks across your blogs.

This separation is useful if you run a personal blog and a separate blog for a project or community. You can customize each one to match its purpose without affecting the others. Just remember to double-check which blog you're editing before you make changes, especially if you're switching between them quickly.

Frequently Asked Questions

Why can't I find the Customize tab on my phone?

Tumblr's mobile app has a simplified settings menu. For full customization options, use a web browser on your phone or tablet instead of the app. Open tumblr.com in Safari, Chrome, or your default browser, log in, and follow the desktop steps. The mobile browser version gives you access to all the same Customize features as the desktop site.

Can I customize my blog without knowing HTML?

Yes. Tumblr's built-in themes and the color and font options in the Customize tab require no coding knowledge. You can create a fully customized blog using only the visual controls. Custom HTML is optional and only needed if you want to design a theme from scratch or modify an existing theme's code.

What happens to my posts if I change my theme?

Your posts stay exactly as they are. Changing your theme only changes how your blog looks visually — the layout, colors, and fonts. All your content, tags, and notes remain unchanged. You can switch themes as many times as you want without losing anything.

Is it safe to use themes from other Tumblr blogs?

Themes from well-known, active theme creators are generally safe. Check the creator's reputation and read recent comments from other users. Avoid themes from inactive or unknown sources. If a theme is from an official Tumblr theme directory or a creator with a long history of sharing themes, it's a safer choice than a random theme from someone you've never heard of.