How to Adjust Text Font Sizes Displayed in Tumblr Blog Themes

Tumblr offers a highly customizable blogging platform where users can fully customize the look and feel of their blog theme. One of the most common customizations is changing the font sizes displayed in the blog theme. Properly adjusting text font sizes can greatly improve readability and accessibility for your blog audience.

Why Adjust Text Font Sizes in Your Tumblr Theme

There are several key reasons why you may want to adjust the text font sizes in your Tumblr blog theme:

  • Improve readability – Increasing font sizes can make text easier to read, especially for users on mobile devices or those with visual impairments. Large blocks of small text can strain the eyes.
  • Enhance visual hierarchy – Adjusting heading font sizes helps establish a clear visual hierarchy, allowing users to quickly scan and comprehend your content.
  • Fix theme issues – Some themes may have font sizes that are too small. Increasing them can fix display and readability issues.
  • Accessibility – Larger font sizes improve accessibility for low vision users. Aim for a minimum of 16px for body text.

Methods to Change Font Size in Tumblr

There are two main methods to change font sizes in Tumblr blog themes:

1. Using Theme Customization Options

Many Tumblr themes come with customization options to change font colors, sizes, etc.

  • Log in to your Tumblr account
  • Go to your blog’s dashboard
  • Click “Customize”
  • Look for font size adjustment options

This method is the easiest but is theme-dependent. Some themes provide more customization options than others.

2. Editing the Theme HTML

For full control and flexibility over font sizes, you can edit the theme’s HTML code:

  • Log in and go to your blog’s dashboard
  • Click “Customize”
  • Click “Edit HTML”
  • Use Ctrl/Cmd + F to find font-size declarations
  • Change the px values to adjust sizing
  • Save changes

This method works with any theme but requires basic HTML/CSS knowledge.

Best Practices When Adjusting Font Sizes

Follow these best practices when changing font sizes in your Tumblr theme:

  • Test extensively – Preview changes across devices and browsers to ensure proper display.
  • Enhance readability – Use larger sizes for body text (16px+ minimum) and adjust heading sizes for hierarchy.
  • Use web safe fonts – Stick with fonts that are widely available to prevent display issues.
  • Improve accessibility – Consider minimum contrast ratios and font size for low vision users.
  • Apply consistently – Change font sizes globally using CSS instead of individual elements.

Step-By-Step Guide to Changing Font Size in Tumblr

Follow this simple step-by-step guide to change text font sizes in your Tumblr blog theme:

  1. Log in to your Tumblr account and go to your blog’s dashboard.
  2. Click on “Customize” located in the top navigation bar.
  3. Click on “Edit HTML” to view your theme’s code.
  4. Use Ctrl/Cmd + F to search for “font-size” in the code.
  5. When you find a font-size declaration, change the px value to adjust the sizing up or down.
  6. For example, to change body text size, find .post-body and set font-size: 18px;
  7. Scroll through the code and modify additional font sizes as needed.
  8. Click “Update Preview” to preview changes before publishing.
  9. Once satisfied, click “Save” to apply changes.

And that’s it! The updated font sizes will now display across your entire Tumblr blog theme. Keep in mind you may need to tweak sizing across various screen sizes to optimize readability.


Adjusting text font sizes displayed in your Tumblr blog theme is simple yet effective way to enhance readability and accessibility. Take advantage of theme customization options or dive into the HTML/CSS code itself to precisely control font sizing. Test extensively and find the right balance of sizes that work for your content and audience.