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How to Change Font Size in PDF Files Easily

If you're wondering how to change font size in PDF, you should be aware that this is not easily done without the right tool. In other words, you'll need to have a proper PDF editor for this, not just an annotation tool like Adobe Acrobat Reader DC or Mac Preview.

The reason is that PDF was intended to be a static format that's not easy to change, making it suitable for viewing on practically any screen or any device without losing key qualities such as layout, alignment, and, of course, font type. So now, let's learn how to increase and reduce font size in PDF using a robust PDF editor called UPDF.

Method 1: How to Change Font Size in PDF

UPDF is a powerful PDF editor that we'll be using to learn how to change font size in a PDF fillable form. In addition, you can also apply a range of changes such as editing the texts, images, links, etc.

how to change font size in pdf form

In addition, to show you how to edit font size in PDF, we'll also be looking at the process of how to change font size in fillable PDFs after you've added text boxes inappropriate places. So, without delay, let's look at two ways that show how to change font size in PDF documents.

Step 1: Go Into Edit Mode

You can use the "Open File" icon on the welcome page of UPDF for this purpose.

To change the font size of your PDF document, you will need to enter the Edit Mode.

To do this, all you have to do is click the "Edit PDF" tab at the left toolbar of the UPDF interface.

how to change font size in pdf text box

Step 2: How Can I Increase or Reduce Font Size in PDF

To change the font size of existing text, first, select the text element to be edited. Once the text is selected, you can change the font size from the floating toolbar near the selection.

  • Increase Font Size in PDF: To increase the font size of the PDF text, you should choose a larger number from the dropdown options. Or you can just type the size of the font yourself.
  • Reduce Font Size in PDF: To reduce the font size of the PDF text, you can use your keyboard to type a smaller size or choose a smaller size from the dropdown list.
how to change font size in pdf text box

Method 2: How to Change Font Size in PDF Text Boxes in the Comment Mode

Now, let's look at how to change font size in PDF text boxes or other comments in the document. Please note that:

  • When you are in the edit mode, you can edit the texts that are the main part of the document, but not comments.
  • When you are in the comment mode, you can edit the texts in the comments, for example, the text boxes, sticky notes, etc.

Step 1: Enter Comment Mode

Click the "Comment" tab on the left toolabr to go into Comment Mode.

Look for the text box for which you want to change the font size and proceed to the next step when you've identified it.

how to edit font size in pdf

Step 2: How to Change Font Size in PDF Text Box Elements

To add a new text box, you need to click the "Text Box" icon and you can set the font size in the pop-up before you add it. After selecting the font size, click anywhere on the document and begin to type. You will see that the font size will be the one you just set.

change font size in pdf

To edit the font size of the existing text box, right-click it and choose "Properties". Or you can double-click the text box. In the floating toolbar, you'll see an option to increase or decrease the font size.

Choose the correct size and then click outside the box to exit editing, and you're good to go! UPDF makes it easy to answer the question of how to change font size in PDF documents.

Tips for Changing Font Size in PDF

There are a couple of things you can keep in mind that will help you handle PDF files in an effective manner using the powerful editing functions of UPDF.

1. It's Better to Have a Copy of the Original File

First, remember that you may need to have a copy of the original file before you start making any changes to the font size and other elements in a PDF. For that reason, it's always a good practice to first create a copy of the file and then edit that version instead of the original. You can do this easily in UPDF by using the "Save As" option and specifying a slightly different name for the copy of the file. For instance, if your original file is called Orig.pdf, you can save the file as Orig_Edit.pdf so there's no confusion later on.

2. Remember to Keep Consistent Font and Style in PDF

Second, it's super easy to match font sizes and types when you add to an existing text element, as UPDF has the capability to match the font and style automatically. But is would be better if you can remember the font size and style yourself. To elaborate, let's say you have a special font in the paragraph section that you want to replicate inside a text box when annotating the file. The normal way to do this would be to remember the font type, style, size, and color, and then apply that to the annotation you're adding.

UPDF is your one-stop PDF solution:

  • You can also manipulate the pages of a PDF file by rotating them, adding pages, removing them, reordering PDF pages, and so on.
  • You can use the advanced OCR feature to transform scanned documents or image-based documents into editable PDFs.
  • It allows you to convert PDF documents into webpages or other file formats, including Word, Excel, Powerpoint, etc.
  • It allows you to add a password to protect your PDF document to restrict unwanted access.


Using UPDF is the easiest thing to do because it's designed to be fun and user-friendly, but there's also a lot of power underlying the attractive and playful design. What's more, there are new features being added all the time so if you start using UPDF today, within the next few iterations, you'll have access to a comprehensive range of PDF tools that cover optimization, redaction, and everything else you will need to handle any type of PDF workload no matter how light or heavy it is. So download UPDF today and start using the robust PDF functionality.