Tumblr themes range from slight modifications of the default blog layout to completely new creations. In the case of the latter, sometimes it can be difficult for complex themes to display well on different screen sizes like those of a smartphone. There are a few ways to ensure that your Tumblr blog looks good on your iPhone.

Mobile Tumblr

Whether your Tumblr blog displays correctly on an iPhone depends on your own personal theme. The best way to determine its flexibility is to check the description of a theme before installing it to your blog. Usually the theme indicates whether it scales to the size of a smartphone. To find themes that do, start with the "Look Good On Any Device" category of Tumblr's theme garden. If this is the case, you can turn off Tumblr's default mobile-optimized layout. Click the gear icon at the top of the website, then "Edit theme." In the sidebar, scroll down and click "Advanced Options," then turn off "Use optimized mobile layout." If you find that your Tumblr theme does not play nicely with your iPhone, keep this setting turned on. It will strip away the theme customizations, but your blog will be much easier to view on a smartphone.

Tumblr App

The free Tumblr app, which can be downloaded from the App Store, includes no support or Tumblr themes, and there's no workaround. The upside is that each blog you visit within the app will load relatively at the same speed and look consistent with the others.