How to change font size of posts on blogger

• Go to Template >> Edit HTML >> and search for ".post-body{" (without quot).
• then you will see following code.

.post-body{margin:0px;padding:0px 16px 0px 0px;font-family:Arial, Helvetica, Sans-serif;font-size:15px;line-height: 20px;}

• Now change 15 to your desired size.