How to Compress PDFs for HMRC and UK Tax Portals

HMRC's online portals have file size limits that catch many people out at the worst possible moment, when they are trying to meet a Self Assessment deadline, submit evidence for a tax credit claim, or prove income for a government check. Most HMRC upload fields accept files up to 3MB, though some sections specify 2MB. For anyone uploading scanned bank statements, payslips, or employment records, that limit is often smaller than the file they have.

This guide covers the documents most commonly needed for HMRC submissions, realistic file sizes for each, and the compression workflow that keeps critical tax details readable.

Documents commonly uploaded to HMRC online

Depending on which HMRC service you are using, you may need to upload:

• P60, employer-issued annual tax summary. Usually a small PDF (100–500KB) from payroll software. Rarely needs compression.
• P45, employment termination form. Similar size to P60 when issued digitally. Scanned paper copies can be 2–5MB.
• Bank statements, typically the largest item. Three months from a UK high-street bank: 5–15MB in PDF form.
• Payslips, digital payslips from payroll portals (such as ePayslips or Moorepay): usually 200–800KB. Printed and scanned payslips: 1–4MB per page.
• Self Assessment supporting evidence, rental income receipts, business expense invoices, professional subscription certificates. Highly variable.
• Letters and correspondence, HMRC letters you are uploading as evidence, or letters from employers and professional bodies. Usually 1–5MB depending on whether scanned or digital.

The HMRC upload limit in practice

HMRC's Personal Tax Account, Self Assessment, and PAYE online services typically accept documents up to 3MB per file, in PDF format. The Help and Support section of HMRC Online specifies PDF, JPG, or PNG, but PDF is the most reliable format for multi-page documents.

Some sections of HMRC's system are older and only accept files up to 2MB. If you are uploading to the National Minimum Wage complaint tool, the tax credits evidence portal, or certain employment checks, assume a 2MB limit unless clearly stated otherwise.

Compressing bank statements for HMRC

Bank statements are the most challenging document to compress for HMRC because they tend to be the largest, the most image-heavy (particularly online banking PDFs from major banks), and the most detail-critical, HMRC checks specific figures, dates, and account identifiers.

The most effective workflow for bank statements is:

1. Delete pages you don't need first

If HMRC is asking for three months of statements and your PDF covers six months, delete the irrelevant pages before compressing. Halving the page count before compression means the compressor applies less aggressive settings to reach the target, preserving more quality on the pages that matter.

2. Compress to 2MB using a target-size tool

Use PDFWhisk's compressor and set a 2MB target (or 3MB if the field allows it). This approach adjusts compression to hit a specific size rather than applying a fixed quality reduction, which gives more predictable results than a "medium" or "high" quality slider.

3. Check these specific details before submitting

• Account number and sort code
• Statement period (start and end dates at the top of each page)
• Opening and closing balances
• Individual transaction amounts and merchant names
• Any direct debits or standing orders HMRC may cross-reference

Zoom to at least 150% when checking, detail that looks acceptable at 100% on a phone screen can be illegible when printed at A4 size or examined on a large monitor by a caseworker.

Compressing payslips for HMRC

Digital payslips from payroll portals (Moorepay, ePayslips, Zellis/ResourceLink, ADP) are usually already small, 200–600KB in most cases. These rarely need compression and typically clear HMRC's 3MB limit without any work.

Printed payslips that have been scanned or photographed are a different matter. A single A4 payslip scanned in colour at 300 DPI is typically 2–4MB. Compressing to 2MB is usually straightforward, but always check:

• Employee name and National Insurance number (must match HMRC records exactly)
• Employer name and PAYE reference
• Pay period (month and year)
• Gross pay, tax deducted, NI contributions

Compressing P60s and P45s

Most employer-issued digital P60s are small (under 500KB) and need no compression. Scanned paper P60s, particularly older ones from previous employment, may reach 3–5MB per page when scanned in colour at high resolution.

For a scanned P60, compress to 2MB. The document typically has a simple layout with black text on white or light paper, so compression handles it well. Check that the PAYE reference, tax year, and all pay/tax figures are crisp after compressing.

Privacy: why bank statements and tax documents should never be uploaded to random sites

Tax documents contain some of the most sensitive information you have: income, employer details, National Insurance number, and in the case of bank statements, a detailed record of every financial transaction. Uploading these to a generic online PDF compressor means sending them to an unknown server with an unknown data retention policy.

PDFWhisk compresses files entirely in your browser using JavaScript. The file never leaves your device during processing. This is why browser-based compression matters especially for sensitive documents, there is no upload, no server, and no data retention window to worry about.

If the file cannot reach the HMRC limit after compression

For scanned colour statements with many pages, reaching 2MB with acceptable quality may not always be possible in a single pass. In that case:

1. Delete as many pages as you can (down to the minimum HMRC needs).
2. Try compressing to 3MB first, some HMRC fields accept this.
3. If you must stay under 2MB, split the document into two or three sections and compress each part separately. Upload them as separate attachments if the portal allows multiple files.

HMRC's digital submission system generally supports multiple file uploads for the same category of evidence. Label files clearly (e.g. "Bank statement January to March 2026 pages 1–6.pdf") and retain the originals until you receive confirmation of acceptance.