File size limits on Spanish government e-offices (2026)

The limits at a glance

Where	Per file	In total
General Electronic Registry (AGE)	10 MB	15 MB, up to 5 documents
Tax Agency (AEAT): supporting documents	128 MB	No limit stated
Social Security: INSS application without certificate	5 MB (4 MB per side of the DNI or NIE)	23 MB per application
Social Marine Institute: replying to requests	5 MB in total

These are the limits published by the e-offices themselves, checked in October 2026. They can change, and a specific procedure may set its own: if the form shows a different figure, follow the form.

General Electronic Registry

This is the registry for filing documents addressed to any body of Spain's central government when there is no specific procedure for it. According to the government's general access point, you can attach up to 5 documents, each up to 10 MB, and no more than 15 MB in total.

If you have more documents, merge them into fewer files within those limits or submit them in another entry. You'll need a digital certificate, an electronic DNI or Cl@ve to sign in.

Tax Agency (Agencia Tributaria)

To submit supporting documents for a tax return or reply to a request, the Tax Agency e-office accepts files of up to 128 MB each. It accepts PDF, JPG, PNG, Word, CSV and ZIP or 7Z archives, among others. The full list is in the “Help” link of each form.

You'll need a certificate or electronic DNI, or Cl@ve if you're an individual.

Social Security

Social Security limits vary by procedure, and they are among the lowest:

INSS benefit application without a certificate: each document can be up to 5 MB, each image of one side of the DNI or NIE up to 4 MB, and the whole application up to 23 MB.
Replying to Social Marine Institute requests: all documents together can't exceed 5 MB.

For Social Security, always check the limit on the page of the specific procedure.

What to do if your file is too big

Compress it to a specific size. With Compress PDF you enter the limit (for example 5 MB or 10 MB) and get the sharpest PDF that fits.
Split it into parts. If it's long, split the PDF by size and upload several files, as long as the procedure accepts more than one.
Remove what isn't needed. Remove blank pages or pages you weren't asked for.
Scan smarter from the start. A black-and-white or greyscale scan at 150–200 dpi is much smaller than a full-resolution colour photo and just as readable.

Leave some margin: if the limit is 5 MB, aim for 4.5 MB. Some e-offices count megabytes differently, and a file right at the limit may fail.

Frequently asked questions

Why does the e-office say my file is too big when it's under the limit?

The total limit for the application may be lower than the sum of your files, or the e-office may count megabytes differently. Stay about 10% under the limit.

Can I upload a ZIP with several PDFs?

It depends on the e-office. The Tax Agency accepts ZIP and 7Z; others don't accept archives. If in doubt, merge the documents into a single PDF.

Does compressing a PDF make it harder to read?

Not if you compress it to a reasonable size. A text document at 150 dpi is perfectly readable. Always check the preview before sending it.

What if I have more than 5 documents for the General Electronic Registry?

Merge them into fewer files of no more than 10 MB each and 15 MB in total, or submit them in another entry.

File size limits on Spanish e-offices