Every designer likely faces this issue at some point: your InDesign file size is just too big! A huge InDesign file size makes the document slow and unwieldy. It also consumes large amounts of vital storage space. Furthermore, a collection of huge InDesign files can even slow down your whole computer and/or server. However, these 4 easy steps will reduce a huge InDesign file size to bring InDesign back to peak performance:
What Can Make an InDesign File So Large?
InDesign is a big program with lots of features to make designers’ jobs easier. Some of these features include a large pasteboard; cache of recently used objects; clipboard of copied objects; and editing history—all features that allows designers to quickly manipulate the document, until a certain point. At a certain point, when there’s too much of these good things, InDesign will slow down designers instead!

Try These X Easy Steps to Shrink Your Huge InDesign File Size
Remove unused objects.
Sometimes our pasteboards accumulate extra materials while we’re experimenting with different layouts.
Instead, tidy up the workspace periodically, and delete artworks you know you won’t use.
The same works with color swatches as well: open the Swatches panel, open the Menu, click Select All Unused, and hit Delete Selected Swatches/Groups.
Condense links.
InDesign records the links of any placed objects within the document. Sometimes if you’re grabbing the same file from multiple sources, InDesign will record the same link as multiple separate links.
Additionally, the duplicate links may persist even with a freshly packaged file.
Instead, relink duplicate links to same file to condense links.
Limit embedded artworks.
Embedded artworks are a great InDesign resource to keep resources in a centralized location. Embedded small artworks don’t add much to the file size, but can reduce the links and provide native editing opportunities, like quick color changes.
However, embedding large artworks can quickly and dramatically make an InDesign file size huge. This is especially true of high-res photos, but even vector artwork causes file size to increase.
After a big clean-up to shrink a huge InDesign file size, Save As a new file.
InDesign likes to hang onto things, for caching purposes. Make InDesign let it go.
After cleaning up the huge InDesign file, Save As a new document. The file size can decrease dramatically with a fresh Save As that somewhere Save doesn’t catch because of the caching.
580 to 29 MB in Successful InDesign File Size Reduction Example:
For example, in a recent work project, I reduced a huge InDesign file size by 95%!
I had been provided a printed brochure file to adapt into urgent web graphics. Inside, a clipping mask cropped a vector hatching texture. Then, the brochure duplicated the clipping a few times to create a pattern.
Yet, that artwork occurred 77 times in the web graphics. Further, each clipped artwork contained 348,343 anchor points, consuming 22 MB per instance. The document consequently racked up a huge InDesign file size of 580 MB.
I grabbed that artwork, copied it into Illustrator, and worked on reducing its file size.
First, I trimmed any points that weren’t visible in the clipping mask using Pathfinder. Next, I used a quick Simplify Path to reduce unneeded points. Finally, I copied the artwork into the pattern that appears in the document from time to time. This combined everything I would need into one .ai file—a single link for InDesign.
This decreased the artwork from 348,343 pts / 22 MB per instance to 40,076 pts / 5 MB total, even with the pattern extension.
By the time I deleted all the embedded artwork clippings and replaced these as an Illustrator linked file, I reduced the huge InDesign file size from 580 to just 29 MB.
Why Are INDD Files Larger than IDML?
(And why are IDML files smaller than INDD?)
You may have noticed when Saving As and/or packaging your InDesign files, the IDML files are always smaller than the regular INDD format.
INDD files track and store a lot of resource data and cache it for later. Because of this caching, INDD files are nearly always larger than IDML.
One of the biggest contributors to a large cache and thus large INDD file size are images. INDD files store image caches that IDML files don’t. As a result, IDML files first open images as just gray boxes until you relink the images.
Designers may choose a faster document with the gray boxes over relinking the images and restoring the cache. On the other hand, working without images can blind the designer to important typesetting. For instance, lots of graphic frames reside near to or within text frames so that restoring the images after typesetting might result in bad overlap.
However, designers may also choose to work with the image cache to observe how all the elements interact. Then, the trade-off can be a huge InDesign file size.
If your InDesign is still running slow even after reducing a huge InDesign file size, try these Adobe InDesign CC performance boosters:
