Automated invoice scanning: how to digitize paper invoices and capture their data

Invoice scanning turns paper invoices into digital images so they can be stored, searched and processed. Automated invoice scanning adds capture: software reads each scan and pulls out the vendor, invoice number, dates, line items and totals as data your ERP can use. Scanning at 300 dpi or higher, one invoice per file, makes that capture faster and more accurate.

This guide covers the ways to scan, the settings that matter, how capture turns scans into data, what processing costs and how to cut paper at the source.

Invoice scanning vs invoice capture

You need both to automate AP. Scanning without capture just moves the typing from paper to screen.

Ways to scan invoices

• In-house scanners

  Desktop or production scanners for modest volumes at one site. Someone opens, preps and scans the mail daily.

• Multifunction printers

  Fine for the occasional invoice; check the resolution and file settings.

• Mailroom or scanning service

  Suppliers mail invoices to a post office box; the provider scans them and sends the images. Suits high volumes or many sites.

• Mobile capture

  Field staff photograph invoices and receipts. Convenient, but image quality varies.

• Redirect to email

  The best scan is no scan: ask suppliers to email PDFs to an AP inbox.

Scanner settings that matter

• 300 dpi or higherThe Tesseract OCR documentation says the engine works best on images of at least 300 dpi.
• Grayscale or black and whiteUse color only where stamps or colored text matter.
• Searchable PDF or multi-page TIFFOne file per invoice, or batches your capture tool can split.
• Deskew and auto-crop onSkewed pages throw off OCR's line detection.
• Blank page removalDrops the empty backs of single-sided invoices.
• Duplex for two-sided invoicesKeeps the terms printed on the back.

Before scanning, remove staples and clips, flatten folds, and keep attachments such as delivery notes and timesheets with their invoice. Then decide how batches get split: one invoice per scan, separator sheets, or a capture tool that splits multi-invoice PDFs for you.

Automated invoice scanning: from scan to data

Once invoices are digital, capture does the rest:

1. Classify and splitThe batch is separated into invoices, credit memos and attachments.
2. ExtractHeader fields and line items come out of any vendor layout, without templates. Docsumo reads invoices and reaches 99% field-level accuracy across 250+ document types.
3. ValidateTotals are checked, vendor details looked up and duplicate invoices flagged. On the Enterprise plan, Docsumo also matches invoice lines to the PO and receipt.
4. ReviewLow-confidence fields go to a person; clicking a field highlights its source line on the scan.
5. Approve and postInvoices are routed for approval, and the data goes to your ERP or accounting system through API and webhooks, or downloads to Excel.

Template-based capture needs a template per vendor layout and breaks when a vendor changes its invoice. AI capture reads new layouts without setup and learns from reviewers' corrections, so beyond a handful of vendors it's the practical choice. More on accuracy in invoice OCR.

What invoice processing costs

Ardent Partners' State of ePayables 2025, a sponsored analyst report, puts the average cost to process an invoice at $9.84. The same report puts the average invoice exception rate at 18.4%. It also finds best-in-class AP teams process invoices at 79% lower cost than their peers.

Keeping scanned invoices as records

For US federal tax purposes, the IRS accepts imaged records kept in an electronic storage system that meets Rev. Proc. 97-22: it must transfer records accurately and completely, index them, reproduce legible copies, and include integrity controls and regular quality checks. Once you've tested the system and set up procedures to keep it compliant, the paper originals can be destroyed. Check with your tax adviser and auditors first, along with any state and industry rules.

Reducing paper at the source

• Publish an AP email address and ask suppliers to send PDFs there instead of mailing.
• Offer a supplier portal for uploads and status checks.
• Use e-invoicing or EDI for your highest-volume suppliers.
• Track paper share by supplier and follow up with the top senders.

The ask is realistic: Ardent found a majority of suppliers (57%) can now send invoices electronically. Every invoice that arrives digitally skips the mailroom and reads cleaner.

The bottom line

Scan paper invoices at 300 dpi or higher, one invoice per file, and feed them straight into AI-based capture that extracts, validates and posts the data. Keep the images in a system that meets IRS requirements, and move suppliers to email or e-invoicing so there's less to scan. For the full process, see accounts payable automation and automated invoice processing.

Book a demo with a few of your own scanned invoices, or start a free trial.

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