Why a single PDF matters

Most corporate expense systems — including Concur, Expensify, SAP Concur, and Oracle Expenses — accept attachments in PDF format and impose a limit on the number of files per claim. Submitting fifteen individual JPEG photographs is not only inconvenient for approvers; many systems will reject it outright.

For HMRC purposes, the requirement is simpler: you must keep records that are accurate, complete, and readable. A single well-organised PDF satisfies this far more reliably than a folder of phone photographs with names like IMG_4782.heic.

What HMRC requires from digital receipt records

HMRC explicitly permits digital records in place of paper originals for Self Assessment and VAT purposes. However, a digital record must meet certain standards to be considered valid:

  • The record must be legible — blurry, heavily shadowed, or poorly exposed photographs may not be accepted.
  • It must show the supplier name, date, amount, and nature of the supply. For VAT reclaims, the supplier’s VAT number must also be visible.
  • Records must be retained for at least six years (five years after the Self Assessment filing deadline for the relevant tax year, plus the current year).
  • The record must not be altered after the fact. Adjusting brightness or contrast for legibility is acceptable; editing the content of a receipt is not.

A PDF created directly from receipt photographs — without editing the underlying content — satisfies all of these requirements. See HMRC’s guidance on keeping business records for the authoritative reference.

The problem with standard PDF merge tools

Generic PDF merge tools — iLovePDF, Smallpdf, and similar services — take your images and stitch them directly into a PDF without any processing. The result is often inadequate for professional or official use:

  • Photos taken at an angle remain skewed, making the text difficult to read.
  • Thermal receipts (the most common type, issued by supermarkets, coffee shops, and most retail point-of-sale systems) photograph poorly. The low contrast between the pale ink and the white paper produces a washed-out image that may not meet HMRC’s legibility standard.
  • The background of the photograph — your desk, your hand, the interior of a bag — appears in the final PDF alongside the receipt, reducing clarity and looking unprofessional.
  • Files uploaded to cloud-based merge tools leave your device, which creates unnecessary privacy exposure for documents that contain financial and vendor information.

A better approach: clean the receipts before merging

The correct sequence for producing a professional receipt PDF is:

  1. Photograph each receipt — natural light is preferable; flash can create glare on thermal paper.
  2. Apply edge detection to identify the receipt boundary within the photograph and correct for camera angle via perspective transformation.
  3. Enhance contrast to make faded thermal ink clearly readable.
  4. Merge the cleaned images into a single PDF, one receipt per page.
  5. Optionally extract key fields — date, total, vendor — into a CSV for bookkeeping or expense report completion.

Steps 2 through 5 can be handled automatically by Tidy Receipts, which runs entirely in your browser. Because all processing happens locally, your receipt photographs are never transmitted to any server.

Step-by-step: combining receipts into one PDF

Step 1 — Photograph your receipts

Place each receipt on a dark or contrasting surface. Hold your phone directly above the receipt where possible, rather than at an angle. Ensure the full receipt is visible within the frame — including the total at the bottom, which is frequently cut off.

For crumpled or curled thermal receipts, flatten them briefly under a book before photographing.

Step 2 — Upload to Tidy Receipts

Open tidyreceipts.app in your browser — on desktop or mobile. Drag and drop your receipt photographs into the upload area, or tap to select them from your photo library. JPEG, PNG, WebP, and HEIC (iPhone) formats are all supported.

Edge detection and contrast enhancement are enabled by default. If you need a CSV of extracted totals alongside the PDF — useful for expense reports where you need to enter amounts manually — enable the OCR toggle before processing.

Step 3 — Review the processed thumbnails

After processing, Tidy Receipts displays each receipt as a side-by-side comparison: the original photograph alongside the cleaned version. Check that the receipt text is legible and that the edges have been correctly identified. If a receipt has been photographed against a white surface and edge detection has not cropped it correctly, the contrast-enhanced version will still typically be an improvement over the original.

Step 4 — Download your PDF

Click Download PDF. The resulting file contains one receipt per A4 page, centred with a white margin. This format is accepted by all major expense management systems and meets HMRC’s legibility requirements.

If OCR was enabled, a Download CSV button will also appear, containing the extracted vendor name, date, and total for each receipt.

Tips for consistent receipt management

Establishing a consistent routine reduces the time spent on receipt administration at month or quarter end:

  • Photograph receipts immediately rather than collecting them in a wallet. Thermal receipts begin to fade within weeks; a photograph taken on the day of purchase will always be more legible than one taken a month later.
  • Name your PDF files descriptively: expenses-march-2026.pdf is easier to locate at tax time than receipts.pdf.
  • Store PDFs in a dedicated folder backed up to cloud storage. HMRC requires records to be retained for six years; a local folder on a single device is an inadequate archive.
  • Separate business and personal receipts at the point of photography. Processing them as separate batches produces separate PDFs, which simplifies accountancy and VAT reclaim submissions.

Summary

Combining receipts into a single PDF is a straightforward process when approached correctly. The key steps are: photograph receipts on a contrasting surface; apply edge detection and contrast enhancement to produce clean, legible images; and merge into a single PDF. For HMRC compliance, ensure each receipt clearly shows the supplier name, date, amount, and — for VAT purposes — the supplier’s VAT registration number.