How to Increase PDF Font Size for Reading, Printing, and Form-Filling

Struggling to read tiny text in a PDF? You can increase PDF font size in several quick ways—whether you’re editing the file directly, enlarging it for printing, or making it easier to view on-screen.

Smallpdf lets you resize text in your browser, but you can also use options like print-scaling, browser zoom, system accessibility tools, or simple text overlays when the original content can’t be edited.

This guide shows you how to increase the font size inside your PDF, edit or replace existing text, add new content with larger fonts, and work around fixed or locked form fields. You’ll also learn how to handle scanned or flattened PDFs, plus what to do when text looks too small after exporting or printing.

How to Increase PDF Font Size Online

Smallpdf’s PDF Editor makes it easy to increase the font size within your PDF file directly in your browser. Follow these simple steps to get it right.

1. Upload your PDF to Smallpdf

1. Open our PDF Editor.
2. Click “Choose Files” to select your PDF or drag and drop it into the upload area.
3. Wait for the file to load in your browser—no software needed to make text bigger in your PDF.

2. Edit existing text or add new text

1. To edit existing text, select “Edit Text.” Any editable fields—like form fields—will activate.
2. To add new text, click “Add Text,” then click anywhere on the page. A text box appears so you can type content with a larger font.
3. Use this option when you need to enlarge PDF text that isn’t directly editable or when you want cleaner spacing.

3. Increase the font size and place your text

1. Click inside the text box or on the field you’re editing.
2. Use the font size menu to increase PDF font size to the level you need.
3. Drag the text box to reposition it if you need more space.
4. This method works for quick adjustments when you want to edit PDF text size online.

4. Download or continue editing

1. Click “Download” to save your edited PDF.
2. Or select “Finish” to move to a screen where you can export the file, share it, or print it.

Increase Font Size in Fillable PDF Forms

Some fillable PDFs use fixed font settings that can’t be changed. If you can’t adjust the field:

1. Click “Add Text.”
2. Place a text box over the form field.
3. Type your content and choose a larger size to increase font size in form fields.
4. This overlay method keeps the layout intact while making your text easier to read.

Troubleshooting: Make PDF Text Larger Without Reformatting

Sometimes increasing font size isn’t as straightforward as clicking a button. Here’s how to handle common issues you might encounter.

Text Won’t Activate When Clicked

Some PDFs store text as part of an image or background layer. If clicking does nothing, the content isn’t editable. Place a new text box over the area and enlarge the text there instead. This keeps the layout intact while letting you adjust the size.

Font Looks Distorted After Resizing

If a PDF was created with uncommon or embedded fonts, enlarging them may cause uneven spacing or distorted shapes. Switch to a standard font—such as Arial or Times New Roman—inside the editor to improve stability and readability.

Content Shifts When You Make Text Bigger

When a text box expands, nearby elements may move or overlap. Reduce the font size slightly, widen the text box, or reposition it so the surrounding layout stays readable. This is common in forms and tightly spaced documents.

Part of the Page Enlarges, but Not the Text You Need

Some PDFs use grouped elements or layers that respond differently to editing. If the wrong section changes size, add a new text box over the specific line you want to adjust. This gives you control without altering the rest of the page.

Fillable Fields Have Size Limits

Certain fields have locked formatting set by the creator. When increasing the size inside the field isn’t possible, place a new text box on top and adjust the font there. This works well for forms with strict formatting.

Scanned Pages Don’t Respond to Text Changes

Scanned PDFs are images, not text layers. Enlarging the page doesn’t make individual words bigger. Add a new text layer on top or run the file through OCR first so the text becomes editable.

Change PDF Font Size for Free on Any Device

Smallpdf’s browser-based PDF editor works on any device with an internet connection. Whether you’re on Windows, Mac, Linux, or using your mobile device, you can increase PDF font size without downloading any software.

• Works on all major browsers (Chrome, Firefox, Safari, Edge)
• Compatible with Windows, Mac, and Linux computers
• Mobile-friendly for iOS and Android devices
• Secure HTTPS encryption protects your documents

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FAQs: How to Increase PDF Font Size

How do I change the font on a PDF?

Use Smallpdf’s PDF Editor to edit text fields that are already editable or add a new text box on top of the existing content. Pick your font and size from the toolbar before downloading. This works on any browser without installing software.

Can I increase PDF font size in a secured or locked PDF?

Sometimes. If the file has editing restrictions or a password that blocks changes, you won’t be able to adjust the original text. If you can open the PDF but can’t edit it, add a text box on top of the locked content and choose a larger font. If the entire PDF is protected with a password, you’ll need that password before making any changes.

Will increasing the font size make my PDF file larger?

Not always. Changing only the font size usually has a small impact because the PDF already contains the font data. File size increases mainly happen when a PDF uses uncommon fonts, or when new text boxes are added. If the file becomes too large, run it through Compress PDF to keep it manageable.

How do I resize a PDF for printing without editing the text?

Use your PDF viewer’s print options. Select Fit to page or set a custom scale (such as 110% or 125%) to make everything print larger. This doesn’t change the file itself—it only enlarges the printed output.

How do I change font size in PDF fillable forms?

Some form fields use fixed font sizes that can’t be edited. If you can’t adjust the field directly, place a new text box over the field, type your text, and choose a larger font size. This gives you a readable result even when the original field is locked.

Why can’t I edit text in my PDF at all?

The text may be part of a scanned image, flattened layer, or a design that doesn’t contain editable fields. Add a text box over the area you want to change or use OCR (Optical Character Recognition) to convert the scan into editable text before adjusting the font size.

Can I increase PDF font size on mobile?

Yes. The PDF Editor works on mobile browsers, so you can upload your file, add or edit text, and resize it on your phone or tablet just like on desktop.