Edit your Tumblr blog's theme to add an additional sidebar to your blog. While many themes provide you with two or more sidebars, you may want to add a sidebar to your existing theme. Using Tumblr's Customize page, you can edit the CSS code for your theme and make changes to its appearance. Copy your theme's original sidebar code, rename and then adjust its CSS characteristics to create a second sidebar.

Step 1

Log in to the Tumblr website.

Step 2

Click the "Customize" button in the right sidebar.

Step 3

Click the "Edit HTML" link on the left sidebar to open Tumblr's HTML editor.

Step 4

Scroll down and highlight your sidebar's CSS code which will vary depending on your blog's theme. For example, locate "#side{" and then highlight the code up to the closing bracket. Your blog's theme may name this something else, such as #sidebar, #lefts or #leftbar.

Step 5

Press "Ctrl-C" to copy your sidebar's CSS code to your clipboard.

Step 6

Move your cursor to the end of your sidebar code and then press "Ctrl-V" to paste a copy of it directly below.

Step 7

Rename your pasted sidebar. For example, change "#side{" to "#side2{" (omitting quotes here and throughout).

Step 8

Change the characteristics of your second sidebar's CSS code so that it does not overlap your first sidebar. For example, if your first sidebar's code includes "left: 1050px;" then you will want to decrease or increase that value so that the sidebars are positioned side by side. Entering "850px;" would place your second sidebar to the right of your first one. You can also change the width and height of your sidebar to avoid overlap.

Step 9

Paste the following code into a new line of text before your closing tag, replacing "Your 2nd Sidebar Name" with the name of your sidebar, such as "side2":

Step 10

Enter any text and HTML code you wish to add to your second sidebar before the

tag. For example, enter "Here is my second sidebar" to add a large title to your second sidebar.

Step 11

Click the "Update Preview" button at the top of the left sidebar to preview your changes to your theme.

Step 12

Click the "Save" button to save changes.