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Custom Page Size in Google Docs: How to Set Any Dimension

Google Docs™ doesn’t let you type in a custom page size. Open File > Page setup, and you’ll see a dropdown with Letter, A4, Legal, and a handful of other options — but no input fields for width and height. If you need 6 x 9 inches for a book, or 8 x 8 for a square format, you’re stuck.

This is one of the most common frustrations with Google Docs™, especially for anyone working on books, planners, photo albums, or anything that requires non-standard dimensions. Luckily, there’s a free workaround.

Why Google Docs Does Not Support Custom Page Sizes

Google Docs™ was designed primarily as a collaborative word processor for everyday documents like reports, essays, and letters. The built-in page setup menu reflects that focus: it offers standard sizes used in offices and schools (Letter, A4, Legal, Tabloid) and a few others, but no custom input.

Unlike desktop applications such as Microsoft Word or Adobe InDesign, Google Docs™ runs entirely in the browser. The engineering team has kept the page setup interface deliberately simple, which means power users who need specific dimensions are left without a native option. The feature request has been sitting in Google’s community forums for years with no response.

That’s where add-ons come in.

The Solution: DocSize for Google Docs™

DocSize is a free Google Workspace™ add-on that gives you full control over page size, margins, and background color in Google Docs™. It was built specifically to solve the custom page size problem.

With DocSize, you can:

  • Set any page width and height down to precise decimal values
  • Choose your preferred unit: inches, centimeters, millimeters, or points
  • Pick from 50+ preset page sizes, including book trim sizes, international standards, and envelope formats
  • Set independent margins for top, bottom, left, and right
  • Toggle between portrait and landscape orientation with one click
  • Change the page background color for design-oriented projects

How to Install DocSize

Getting started takes less than a minute:

  1. Visit the DocSize listing on the Google Workspace™ Marketplace.
  2. Click Install and grant the required permissions.
  3. Open any Google Docs™ document.
  4. Go to Extensions > DocSize > Change Document Size.
  5. The DocSize sidebar will appear on the right side of your document.

How to Set a Custom Page Size

Once the DocSize sidebar is open:

  1. Select your unit (inches, cm, mm, or points) from the unit dropdown at the top.
  2. Enter your desired width and height in the input fields. You can type exact decimal values, such as 5.5 x 8.5 inches.
  3. Click Apply to resize your document instantly.

Your document immediately resizes. No page refresh, no re-opening — just keep working.

If you would rather pick from a list instead of typing dimensions manually, DocSize includes over 50 built-in presets. Just select your size from the preset dropdown and hit Apply.

For a broader walkthrough of changing page sizes in Google Docs™, including the built-in method and its limitations, see our guide on how to change page size in Google Docs.

Common Custom Page Sizes and When You Need Them

Here are the most frequently requested custom page sizes that Google Docs™ does not offer natively, along with the projects that typically require them.

6 x 9 Inches — Books and Amazon KDP

The 6 x 9 inch trim size is the most popular choice for self-published paperbacks, especially on Amazon Kindle Direct Publishing (KDP). It works well for novels, non-fiction, memoirs, and general trade books. If you are writing and formatting a book in Google Docs™, this is likely the size you need.

We have a dedicated guide on formatting a book for Amazon KDP in Google Docs that walks through the full process, including margins, font choices, and export settings.

5 x 8 Inches — Novellas and Compact Books

The 5 x 8 inch format is common for shorter works like novellas, poetry collections, and small guidebooks. It feels compact in the hand and keeps page counts manageable for shorter manuscripts.

5.5 x 8.5 Inches — Trade Paperback (Digest Size)

Also known as “digest size,” 5.5 x 8.5 inches is the standard trade paperback format used by many traditional publishers. It is the go-to choice for literary fiction, self-help, and business books. This is also a common size for workbooks and journals.

8 x 10 Inches — Photo Books and Portfolios

The 8 x 10 inch format is widely used for photo books, art portfolios, coffee table books, and cookbooks. It provides ample space for large images while remaining a manageable physical size.

Square Formats — Scrapbooks, Children’s Books, and Social Media

Square page sizes like 8 x 8 inches and 12 x 12 inches are popular for scrapbooks, children’s picture books, and print materials designed to match social media aesthetics. Google Docs™ has no square presets at all, making an add-on essential for these projects.

A5 (148 x 210 mm) — International Standard

A5 is exactly half the size of A4 and is widely used outside the United States for notebooks, planners, booklets, and small-format publications. While Google Docs™ does include A5 in its page setup dropdown, many other international sizes like A6, B6, and C5 are missing entirely.

Setting Custom Margins Alongside Custom Sizes

Changing your page size is only half the equation. Most projects that require a custom page size also require specific margins. Book interiors, for example, need a wider inside (gutter) margin to account for the binding, while the outside margin can be narrower.

DocSize lets you set each margin independently:

  • Top margin: Space above the body text, often used for running headers.
  • Bottom margin: Space below the body text, typically matching or slightly larger than the top.
  • Left margin: On a right-hand page, this is the inside (gutter) margin for bound books.
  • Right margin: On a right-hand page, this is the outside margin.

You can enter margin values in the same unit you chose for the page size (inches, cm, mm, or points), and all four margins can be different. This level of control is critical for print-ready layouts.

For example, a typical 6 x 9 inch book might use:

  • Top: 0.75 inches
  • Bottom: 0.75 inches
  • Inside (left): 0.875 inches
  • Outside (right): 0.5 inches

With DocSize, you enter these values directly in the sidebar and apply them alongside your page size in a single step.

Tips for Working With Custom Page Sizes

  • Check your printer or publisher requirements first. Before setting a custom size, confirm the exact dimensions required by your print service, publisher, or platform (like KDP). Getting this right from the start saves reformatting later.
  • Use the correct unit. If your specifications are in millimeters, use millimeters in DocSize rather than converting manually. The built-in unit conversion eliminates rounding errors.
  • Preview before exporting. After setting your custom size, scroll through the entire document to make sure text, images, and tables fit correctly within the new dimensions.
  • Export as PDF for printing. When your document is ready, go to File > Download > PDF Document. The PDF will preserve your exact custom page size, which is what most printers and publishing platforms expect.
  • Save a template. If you use the same custom size repeatedly, set it up once in a blank document and save that document as your personal template. Each time you start a new project, duplicate the template.

Frequently Asked Questions

Can I set a custom page size in Google Docs without an add-on?

No. As of early 2026, Google Docs™ does not provide any way to enter custom page dimensions. The built-in File > Page setup menu only allows you to select from a fixed list of preset sizes. An add-on like DocSize is the only way to set a custom page size.

Is DocSize free to use?

Yes. DocSize is completely free. There are no premium tiers, no feature limits, and no trial periods. You can install it from the Google Workspace™ Marketplace and use all of its features at no cost.

Will my custom page size be preserved when I share the document or export it as a PDF?

Yes. Once you apply a custom page size with DocSize, it becomes the document’s actual page size within Google Docs™. Collaborators will see the same dimensions, and exporting to PDF will produce a file with the exact page size you set. The recipient does not need DocSize installed to view the document at the correct size.

Does DocSize work on mobile or tablet?

DocSize is a Google Workspace™ add-on that runs in the sidebar of the desktop (browser) version of Google Docs™. It is not available in the Google Docs™ mobile apps for Android or iOS. However, once you apply your custom page size on desktop, the document retains that size everywhere, including on mobile devices.

Ready to Set Your Custom Size?

Grab DocSize from the Google Workspace™ Marketplace — it’s free, takes 30 seconds to install, and works with any Google account.