GST, income-tax and MCA uploads: size limits and how to meet them

By Aman, founder of FABX Labs · Updated 17 September 2026 · 4 min read

For accountants and small businesses. The document limits on the GST, income-tax and MCA portals, how to get registration documents, notice replies and eForm attachments under them, and why you compress before signing.

Tax and company-law portals each set their own document limits. The limits aren't hard to meet, but the right method differs by portal, and one mistake (compressing a signed PDF) can make a filing invalid.

These are the limits commonly reported for recent use. The upload screen you are using always shows the limit it enforces. Use that number.

GST registration: the 100 KB squeeze

The GST registration form stops at every document tab with the same rule: PDF or JPEG, 100 KB at most. A one-page electricity bill from a copy shop is often around 400 KB, and a rent agreement can run to several pages.

• Use greyscale for bills and agreements, and black and white for typed pages. Colour uses up the budget.
• Keep the name, address and dates readable. The officer compares the address with what was typed in the form, and a blurred scan is a common reason for a clarification notice.
• If an eight-page agreement still won't fit, upload the pages the officer needs (the first page, the address page and the signature page) and keep the full copy ready.

Income-tax replies: split, don't flatten

Evidence for e-proceedings is usually long: a year of bank statements, a ledger, a stack of bills.

• Statements and ledgers downloaded as PDFs are text. Don't compress them into images; split them into parts under 5 MB instead. They stay sharp and searchable.
• Scanned bills can be compressed; greyscale is fine.
• Name the parts so the officer can map them to your reply: "Annexure A, bank statement, part 1 of 3".
• Check the response screen for the number of attachments and the combined limit.

Bank statements often arrive password-protected. If you have the client's password, open a copy on your own computer, not on an upload site.

MCA: compress first, then sign

This is the rule that matters most for company secretaries.

A digital signature (DSC) adds a certificate chain, and often a timestamp, to the PDF. That can push a 5.9 MB file over a 6 MB limit. And once a PDF is signed, any tool that rewrites it, including every compressor, invalidates the signature.

So the order is always:

1. Compress the unsigned attachment, aiming a little under the cap. About 5.5 MB is a sensible working number for a 6 MB limit.
2. Sign it.
3. Attach it.

If a scanned annual report still won't fit, split the unsigned original into parts, sign each part, and attach them in order.

Splitting anything to a limit

For any portal with a per-file cap, splitting by size keeps pages exactly as they are and in order.

Client confidentiality

These documents hold PAN, account numbers, turnover and salaries. Every tool here works inside your browser. Files are processed on your computer and never uploaded, and you can switch off the internet after the page has loaded. That makes them suitable for client work where uploading to a third-party website isn't.

Checklist for a practice

1. Read the limit on the actual upload screen, not from memory.
2. Text PDFs: leave them alone if they fit; split them if they don't.
3. Scans: greyscale or black and white, then compress to the limit.
4. DSC files: compress or split before signing, never after.
5. Name the parts as annexures, in order, and refer to them in the reply.
6. Keep originals of everything, especially signed files.

Tools used in this guide

More guides

• UPSC: the photo, the triple signature and the 10-day rule
• Form 16, ITR-V and bank statements: finding the PDF password you already have
• SSC photo and signature rules, explained
• Split a large PDF to fit a 5 MB or 10 MB limit