Where the number comes from
CM/ECF reports its own current ceiling. From the CM/ECF startup page, the Court Information link shows the Maximum PDF File Size the system will accept at that moment — for this district, 75 MB — alongside a separate 100 MB maximum that applies when documents are merged.
That page is the most reliable source there is, because it is the system doing the enforcing rather than a notice describing it. It is worth checking whenever a filing is refused for size: districts revise these figures without much announcement, and secondhand summaries go stale quietly.
Federal limits are set district by district rather than nationally, so a figure learned in one district says nothing about another. There is no national CM/ECF number.
Why a filing gets this large
At 75 MB an ordinary brief is nowhere near the ceiling — a text-native PDF of fifty pages is typically well under a megabyte, because it stores letterforms and positions rather than pictures of a page. Filings that pass 75 MB are almost always scans, and usually color scans at high resolution.
A page captured at 600 DPI in 24-bit color can occupy several megabytes on its own. Across an exhibit of a few hundred pages that reaches 75 MB without the exhibit being unusual. Photographs straight from a phone and screen recordings are the other common causes.
Because the excess is image data rather than text, resampling is disproportionately effective: reducing the embedded images to a resolution matched to how the document is actually read commonly removes most of the file while the text on the page stays clearly legible.
Checking the limit yourself
CM/ECF reports its own current ceiling. From the CM/ECF startup page, the Court Information link shows the Maximum PDF File Size the system will accept at that moment. That figure is authoritative for the system you are actually filing into, and it is worth a look whenever a filing is refused for size — districts raise these limits without much announcement, and a number you remember from last year may simply be out of date.
If the file is an exhibit
Lossy compression alters a file. Every byte of the output differs from the input, even where the page looks identical on screen, and that can matter if the document's authenticity is ever contested. ShrinkWrit shows the SHA-256 hash of the file you started with and the file it produced, so the change is documented rather than invisible.
The lossless mode strips metadata and repacks the file without touching a single pixel or sample. It saves less, and on a heavily scanned document it may not reach the limit at all — but when it does, the image data is bit-for-bit what it was. Your original is never modified either way; the output is always a new file.
Common questions
- Is the D. Colorado limit 25 MB or 75 MB?
- CM/ECF reports 75 MB per document. The 25 MB figure appears in various third-party summaries but is not published by this court, and the system itself accepts more.
- What is the 100 MB figure?
- A separate maximum that applies when CM/ECF merges documents together, rather than to a single uploaded PDF.
- How do I check the limit myself?
- Open the Court Information link from the CM/ECF startup page. It reports the Maximum PDF File Size the system is enforcing right now, which is more current than any notice describing it.
- Will compressing destroy the searchable text?
- Not in the normal path. ShrinkWrit downsamples the images embedded in a PDF and leaves text objects untouched, so text stays selectable and searchable. If a file can only be made to fit by rasterizing the pages, the result panel says so explicitly, because that does discard the text layer.
The 75 MB figure on this page was last checked against the court’s own notice on Jul 2026. Limits change without much announcement — confirm it at the source before you file.