# How does Briefcase detect duplicate invoices?

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How does Briefcase detect duplicate invoices?. Briefcase checks every new document against the documents already in Briefcase for the same client. It compares.

Briefcase checks every new document against the documents already in Briefcase for the same client. It compares four details: the supplier or customer, the amount, the date and the invoice reference.

-   **Exact match** (all four agree): the new document is archived automatically as a duplicate.

-   **Close match** (three of the four agree): Briefcase's AI compares the two documents themselves before deciding.

Because the check uses the details on the document, the same receipt photographed and later scanned is caught as a duplicate, even though the images differ. A reference that was changed afterwards, for example in Xero, doesn't stop a match when the other details agree.

Duplicate detection only compares against documents processed through Briefcase, not against historical bills that were entered in Xero or QuickBooks before you started using Briefcase.

## Expense claims with a summary spreadsheet

If you upload a summary sheet together with its receipts, Briefcase reads the sheet as a transaction in its own right. The sheet and the receipts have different suppliers and amounts, so they aren't duplicates of each other, and the claim total is counted twice. Instead:

1.  Upload the receipts only, one employee at a time, with a note such as "Expense claim for Jane Smith".

2.  If you want the summary sheet on file, open one of the receipts in the claim and use **\+ Add** to attach it. It stays with that item and doesn't change the total.

3.  Use the same full name each time, otherwise Briefcase creates a separate contact and claim for each spelling.

Found a duplicate we missed? Let us know and we'll look into it.

## More in Uploading documents

-   [Auto-forward your whole inbox: automatic transaction detection and junk filtering](https://briefcase.so/articles/automatic-transaction-detection-and-junk-filtering)
-   [How does Briefcase handle CIS invoices?](https://briefcase.so/articles/how-does-briefcase-handle-cis-invoices)
-   [How do I add additional documents to an invoice?](https://briefcase.so/articles/how-do-i-add-additional-documents-to-an-invoice)
-   [How do I merge multiple invoices together that I don't want to have split?](https://briefcase.so/articles/how-do-i-merge-multiple-invoices-together-that-i-don-t-want-to-have-split)
-   [How do I move an invoice between the costs and sales inboxes?](https://briefcase.so/articles/how-do-i-move-an-invoice-between-costs-and-sales)
-   [How do I permanently delete a document?](https://briefcase.so/articles/how-do-i-permanently-delete-a-document)
-   [How do I upload images using OneDrive and Power Automate?](https://briefcase.so/articles/how-do-i-upload-images-using-onedrive-and-power-automate)
-   [How to upload multiple pictures to Briefcase via WhatsApp](https://briefcase.so/articles/how-do-i-upload-multiple-pictures-in-one-go-on-whatsapp)
-   [Email Upload](https://briefcase.so/articles/email-upload)
-   [Web Upload](https://briefcase.so/articles/how-do-i-upload-documents-to-briefcase)
-   [How to upload receipts and invoices to Briefcase via WhatsApp](https://briefcase.so/articles/whatsapp-upload)
-   [What types of documents can I upload to Briefcase?](https://briefcase.so/articles/what-types-of-documents-can-i-upload-to-briefcase)

## Still need help?

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