Compress a PDF for a USCIS filing

The limit is not the hard part

USCIS allows 12 MB per file, which is generous. Canada allows 4 or 5 MB, the UK 6 MB, Australia 5 MB. If you are used to those, USCIS feels roomy.

The rule that actually bites is the one in the sentence before it. Their guidance says:

"Use a scanner or take pictures of each document. Make sure each image you attach is clear and that all text is readable. Files must not be larger than 12MB in size."

Readable is a requirement, not advice. And the moment you are bundling several hundred pages of evidence — as anyone filing a marriage-based case is — those two rules start pulling against each other.

What 12 MB actually holds

This is the number nobody publishes, so here it is, from measuring real scanned documents:

Those come from two thresholds we measured rather than guessed: a greyscale scanned page needs about 120 KB to stay comfortably readable, and a black-and-white one about 35 KB.

The difference is not a trick. A scan of a printed page is black marks on white paper. Storing 256 shades of grey for it spends most of the file on the paper — its tint, the shadow at the spine, the sensor noise — and none of that is information a reviewing officer needs. Converting to black and white spends those bytes on resolution instead.

Same 12 MB. Three times the pages. Sharper text.

"Do not encrypt or password protect your files"

That is USCIS's own wording, and it is the third major immigration portal in a row to say it — Australia's ImmiAccount and the UK's UKVCAS both refuse protected files too. It is worth treating as a general rule rather than a quirk of one system.

The reason it catches people is that a protected PDF gives you no sign that it is protected. It opens fine on your machine, because your reader remembered the password months ago. Bank statements are the usual source; many banks issue them protected by default, and bank statements are exactly what these applications ask for.

Remove the password before uploading. It takes seconds, and the alternative is a Request for Evidence and several months.

Translations double your files

USCIS requires a certified English translation in addition to the original — not instead of it. Every foreign-language birth certificate, marriage certificate or bank letter is therefore two documents.

People routinely plan their file sizes around the originals and then discover the translations. Count them at the start.

One file per slot, so combine deliberately

Each evidence field takes a single file. That means a set of twelve payslips should be one PDF, in date order, not twelve uploads — easier for an officer to read, and it keeps the categories tidy.

Combine first, compress second. Compressing twelve files separately and then merging them gives a worse result than merging once and compressing the whole thing.

When compressing is the wrong answer

If you have 300 pages of colour scans and a 12 MB budget, that is 40 KB per page. No compressor on the internet will make that readable, and USCIS explicitly requires it to be.

The fix is upstream: rescan in black and white at 200–300 DPI. A scanner discards the paper colour and the shadows at source, and the result is both smaller and easier to read than the compressed colour version. Alternatively, split the bundle across the evidence categories USCIS gives you rather than forcing everything into one slot.

It takes longer than clicking a button. On a filing that costs thousands of dollars and a year of waiting, it is still the right answer.

The order that saves time

1. Remove passwords first, or you will compress a file you then have to redo.
2. Count the translations — every foreign-language document is two files.
3. Merge what belongs together, in the order an officer would read it.
4. Compress to about 10 MB, not 12. Leave the margin.
5. Open the result and read it. If you cannot read a payslip on screen, neither can

the person deciding your case.