How to Change Document Size in Adobe Illustrator: A Complete Guide

As a veteran graphic designer, one of the most frequent questions I get from Illustrator beginners is "How do I change the size of my document?" It‘s an essential skill to master, whether you‘re creating layout mockups, logos, digital illustrations, or print designs.

Thankfully, changing the document size in Illustrator is quick and easy once you know where to look. In this step-by-step guide, I‘ll show you two methods to resize your artboards and overall document dimensions. I‘ll also share essential tips and best practices to help you avoid common pitfalls when scaling your designs.

But first, let‘s look at some of the most common use cases for resizing Illustrator documents. Knowing the "why" behind this fundamental skill will help you work smarter and more efficiently in your design projects.

4 Reasons You May Need to Resize Your Illustrator Document

There are countless scenarios that call for modifying the size of your Illustrator file. But in my experience, it typically boils down to one of four reasons:

1. Incorrect dimensions from the start. We‘ve all been there – you dive into a new project with an inspired idea, only to realize you set up the document at the wrong size. Rather than starting over, you can easily adjust the artboard dimensions to get back on track.
2. Repurposing artwork for a new medium. Thanks to Illustrator‘s vector workflow, it‘s simple to adapt a design for multiple applications. For example, you might scale down a poster design to create a postcard version, or enlarge a logo to fit on a billboard mockup. Resizing allows you to "recycle" your hard work.
3. Creating multiple sizes for digital media. Digital designers often need to generate multiple versions of web banners, social media images, or app layouts to accommodate different screen sizes and ad specs. Illustrator makes it painless to set up all the requisite sizes as separate artboards within a single file.
4. Adding bleed and trim marks for print. If you‘re preparing artwork for professional printing, your document size will need to account for bleeds, which are small amounts of extra image that extend beyond the final trim size to accommodate slight cutting variations. You may also need to add printer‘s marks like crop marks and registration marks, which sit outside the live image area.

With these common use cases in mind, let‘s dive into the two primary ways to change document size in Illustrator.

Method 1: Resize Your Document Using the Document Setup Dialog Box

The quickest and easiest way to change the overall dimensions of your Illustrator file is via the Document Setup dialog box. This method is ideal when you want to scale all artboards in your document simultaneously. Here‘s how:

1. Go to File > Document Setup in the top menu bar, or use the keyboard shortcut Alt+Ctrl+P (Win) or Option+Command+P (Mac).
2. In the Document Setup dialog box, click the "Edit Artboards" button to unlock the Width and Height fields.
3. Enter your desired dimensions in the Width and Height fields. You can type values in any of Illustrator‘s supported units, including pixels, points, inches, millimeters, centimeters, or picas. For example, typing "1920px" will set the width to 1920 pixels.
4. Choose your desired unit of measurement from the Units dropdown. This determines the primary unit displayed in panels and dialog boxes. It‘s best to choose the unit that matches your final output – pixels for web, inches or mm for print, etc.
5. If your design requires bleed, enter the bleed amounts in the Bleed fields. You can specify different values for top, bottom, left, and right. For example, entering ".125 in" will set a 1/8 inch bleed on all sides. Illustrator will automatically add bleed guides to your artboards as a visual reference.
6. Optionally, specify the color mode in the Advanced section of the Document Setup dialog. The default is RGB for digital designs, but you may need to switch to CMYK if you‘re creating artwork for a 4-color print process. Illustrator will convert all color values in the document to the new color space.
7. Click OK to apply your new document size settings.

That‘s it! Illustrator will instantly resize all artboards and their contents to fit the new dimensions. If you had any objects extending beyond the original artboard bounds, they will be clipped or repositioned as needed.

One important thing to note is that by default, Illustrator will scale strokes and effects when you resize the overall document. That means any lines, borders, drop shadows, etc. will increase or decrease in size along with everything else.

In most cases this is desirable for maintaining the proportions and balance of your design. But if you want to keep these elements at their original absolute sizes, simply uncheck the "Scale Strokes & Effects" option in the Document Setup dialog before committing your changes.

Method 2: Resize Individual Artboards with the Artboard Tool

The Document Setup dialog is great for changing all artboards to a consistent size in one fell swoop. But there may be times when you need finer control over the dimensions of individual artboards within your document.

For example, let‘s say you‘re designing a series of web banners for a campaign. You‘ll likely need to create the standard IAB ad sizes – 300×250, 728×90, 160×600, etc. – as separate artboards so you can export them as individual assets.

In this case, you‘ll want to use Illustrator‘s Artboard Tool to resize one artboard at a time. Here‘s the process:

1. Select the Artboard Tool (Shift+O) from the Tools panel. If you don‘t see it there, look under the Move Tool, where it‘s nested by default.
2. Click the edge of the artboard you want to resize to select it. You should see a dashed bounding box appear around the artboard.
3. To change the artboard dimensions, simply click and drag any of the handles on the bounding box. The cursor will change to a double arrow, indicating you can resize from that edge or corner.
4. Drag outward to increase the artboard size or inward to decrease it. As you drag, Illustrator will display a temporary size label so you can gauge the new dimensions.
5. To constrain the aspect ratio while resizing, hold the Shift key as you click and drag a corner handle. This is handy for scaling artboards proportionally.
6. Alternatively, you can type exact dimensions in the Width and Height fields in the Control Panel or Properties Panel.
7. To reposition the artboard on the canvas without changing its size, click and drag the small square target at the center of the artboard.
8. Repeat the above steps for any additional artboards you want to resize in your document.

If you want even more control, you can double-click an artboard with the Artboard Tool to bring up the Artboard Options dialog box. This lets you enter precise dimensions, choose a preset size from the dropdown (like Letter, A4, 16:9 video, etc.), change the orientation, and even give the artboard a custom name.

To add a new artboard at a specific size, simply click and drag on the canvas with the Artboard Tool. Illustrator will create a new artboard at the dimensions implied by your drag area. You can also click the New Artboard button at the bottom of the Artboards panel and choose a preset.

Resizing Multiple Artboards at Once

When working with numerous artboards, resizing them one by one with the Artboard Tool can be tedious. Fortunately, Illustrator offers a way to resize multiple artboards simultaneously using the Artboards panel.

To open the Artboards panel, go to Window > Artboards. You‘ll see a list of all artboards in your document, along with their dimensions and any custom names you‘ve assigned.

To resize multiple artboards:

1. Shift+click or Ctrl/Cmd+click to select the artboards you want to resize in the Artboards panel
2. Click the Artboard Options button (gear icon) at the bottom of the panel
3. In the Artboard Options dialog, enter the new Width and Height
4. Choose whether to anchor the artboards from the center or any of the four corners using the 9-point proxy
5. Click OK to apply the new dimensions to all selected artboards

This method is a huge time-saver compared to resizing a bunch of artboards one at a time with the Artboard Tool.

Common Document Sizes for Print and Digital Media

When creating a new document or resizing an existing one, it helps to be aware of the common size standards for your intended medium. Here are some of the most frequently used document sizes in the US:

Print

• Letter: 8.5 in x 11 in
• Legal: 8.5 in x 14 in
• Tabloid: 11 in x 17 in
• Poster: 18 in x 24 in, 24 in x 36 in
• Postcard: 4 in x 6 in, 5 in x 7 in
• Business card: 3.5 in x 2 in

Digital

• 1080p HD video: 1920 px x 1080 px
• 4K Ultra HD video: 3840 px x 2160 px
• Instagram post: 1080 px x 1080 px
• Facebook cover photo: 820 px x 312 px
• Twitter header: 1500 px x 500 px
• Leaderboard banner ad: 728 px x 90 px
• Half page ad: 300 px x 600 px

When in doubt, it‘s always best to check the specifications provided by your printer or ad network. They will have detailed guides on document sizes, bleeds, margins, color space, and other technical requirements for your particular project.

How Do Illustrator‘s Supported Units Work?

You may have noticed that Illustrator allows you to work in a variety of measurement units – points, picas, inches, millimeters, centimeters, and pixels. But what do these different units actually mean, and when should you use them?

Here‘s a quick primer:

• Points (pt): A standard unit of measurement in typography. There are 72 points in one inch. Points are commonly used for print media.
• Picas (pc): Another typographic unit, equal to 1/6 of an inch or 12 points. Picas are often used for column widths and margins in print layouts.
• Inches (in): The standard imperial unit of length in the US and a few other countries. Inches are widely used for print design and to define screen sizes.
• Millimeters (mm): A metric unit equal to 1/1000 of a meter. Millimeters are commonly used for print design layouts in most countries outside the US.
• Centimeters (cm): A metric unit equal to 10 millimeters. Centimeters are sometimes used interchangeably with millimeters in print design.
• Pixels (px): The smallest unit of a raster image that can be displayed on a digital screen. Pixels are used for all digital design work, from web banners to app UI.

As a general rule of thumb, use points, picas, inches, or millimeters when creating artwork for print, and pixels when designing for screens. Illustrator makes it easy to switch between units on the fly using the Units dropdown in panels like Transform and Properties.

Key Takeaways for Resizing Illustrator Documents

We covered a lot of ground in this guide, so let‘s recap the most important points:

• Use the Document Setup dialog (Alt+Ctrl+P) to change the overall document size and scale all artboards simultaneously
• Use the Artboard Tool to resize individual artboards (hold Shift to constrain proportions)
• You can name artboards and choose preset sizes in the Artboard Options dialog
• To resize multiple artboards at once, select them in the Artboards panel and click the Artboard Options button
• Choose the appropriate unit of measurement for your project – usually pixels for web/UI and inches or millimeters for print
• Don‘t forget to add bleeds if you‘re sending artwork to a professional printer
• Be mindful of raster image resolution when significantly scaling up a document with embedded images to avoid pixelation

By mastering these fundamentals of document resizing, you‘ll be able to adapt your Illustrator designs to virtually any use case with speed and precision. The key is to understand your final output requirements from the start and plan your document setup accordingly.

I hope this in-depth tutorial gave you the knowledge and confidence to resize your Illustrator files like a pro. For more expert tips and techniques, check out the rest of our blog or enroll in one of our Adobe Illustrator courses. Happy designing!

Cover image: Adobe Stock