Comparisons and alternatives

Price Double Check vs ChatGPT for invoices

Last checked 7 September 2026 · This page is provided in English.

Price Double Check vs ChatGPT for invoices comes down to frequency. For one invoice, once, ChatGPT is enough and free: paste the invoice and price list and ask which lines differ. For the same check every month, forward the supplier's email instead: the price list stays on file, the arithmetic is proved, and the differences come back by email unasked.

The two are not rivals for the same moment. A chat model is a reader you talk to; a matching service is a clerk who remembers. This page sets out what each does with a supplier invoice and a price list, what each costs in September 2026, and where the line between them falls for a purchaser at a distributor, importer, retailer or restaurant.

What ChatGPT does well with an invoice

Upload a PDF invoice and a spreadsheet price list to ChatGPT, ask it to list the lines where the billed unit price is not the list price, and on a clean pair of documents it will answer in a minute. It reads layouts a rule-based parser has never seen, it copes with a description split over two lines, it understands that Pcs, Tn and tk are the same unit, and it explains its answer in plain language. It is also free at the quantities a small buyer has: the ChatGPT pricing page lists the Free plan at €0 with limited messages with uploads, Go at €8 a month with more uploads, and Plus at €23 a month with expanded messages and uploads, as shown to a visitor in the euro area. Third-party guides quote the US prices as $8 and $20.

Claude, the other consumer model a purchaser is likely to have, sits at the same price: Free at $0, Pro at $20 a month or $17 on an annual plan, and its help pages state the upload limits plainly, 20 files per chat, 500 MB each, PDFs to 1000 pages. OpenAI's pricing page describes uploads as limited, more and expanded per plan and does not print counts; its help centre gives figures that third-party trackers repeat, and we do not restate them here.

So if you receive two invoices a month from one supplier and the price list changes once a year, do this with a chat model. We would. The rest of this page is about the purchaser who receives thirty invoices a month from six suppliers and has done the chat version twice.

What a chat session cannot hold

Four things separate a monthly control from a one-off question, and none of them is the quality of the reading.

1. Memory of the price list between months. The list in force is a document that arrived in March; the invoice arrives in June. A chat session starts empty, and a project folder holds files, not the knowledge of which list was valid on which date, or that the July order proposal quietly carried a new price before the file called a price list did.
2. An arithmetic gate. Before any line is compared, the sum of the lines must equal the printed total to the cent. In our validation chain that gate was the only thing that caught a quantity and a price fused into one token, 1 15,00 read as 115.00. A model that misreads a digit does not stop; it produces a confident table with one wrong row.
3. Line-level restraint. Across 442 lines a matching service must produce zero invented matches, and it can, because it matches by item code and refuses anything else. A model asked to match 335 lines whose descriptions differ from the price list wording will match most of them by meaning and be right most of the time, which is not the same thing as being auditable.
4. It happens by itself. The check that is worth money is the one nobody remembers to run in the week the delivery lands. A forward rule in a mailbox runs on the day the invoice arrives; a chat session runs when someone opens it.

The pricing pages on both sides describe memory as a feature that is limited on free plans and expanded on paid ones. That is memory of your conversations. Neither vendor claims that the model will, unprompted, notice that the pack size on line 14 shrank while the price stayed the same, and it would be unfair to expect it.

Price Double Check vs ChatGPT for invoices in one table

Read Price Double Check vs ChatGPT for invoices as two tools rather than a contest with a winner. The chat column is better at reading an odd layout and at answering a follow-up question. The service column is better at doing the identical thing on the 30th invoice exactly as on the first, and at telling you when it could not.

What breaks a naive reading, on real documents

We built the matching on one real chain of documents, 30 of them between a sports-nutrition manufacturer, a Baltic distributor and a retailer, and kept a list of what tripped the parser. It is a fair test for any reader, human, model or code, because every item was met on a real page.

• Item codes with suffixes: 5116_1 on the invoice is 5116 on the price list. A code is the only safe key, and even the key needs normalising.
• The same code twice in the price list at the same price with a different pack. The invoice prints no pack size at all, so the shrinkage is visible only price list to price list.
• Three versions of one invoice with the same number and different totals. The identity of a document is supplier, kind and number, and a credit note prints the number of the invoice it cancels, not its own.
• Estonian documents with a decimal comma, one Estonian document with a decimal point and five-digit quantities, Spanish documents with a point. The separator belongs to the document, not to the language.
• Floating-point noise in spreadsheets: 1.1760000000000002 against 1.176 gives 43 phantom price changes between two files unless every number is rounded on the way in.
• A price list that states no currency, no VAT rate, no validity date and no version.

A chat model handles several of these gracefully and a few of them silently. The difference that matters for a control is the word silently. When we cannot match a line we say so and print its amount; the reply lists 14 unmatched lines out of 382 compared in the validation chain, each for a reason we can name, and 0 misread. That is the number a model cannot give you about its own output. We wrote up why a parser is not an answer on its own, and the same holds for a model.

What a miss costs, and what the check costs

In the validation chain one line billed 17.75 percent above the list price ate 91 percent of the margin on that delivery. Forty-one real price differences sat in 382 compared lines, and 11 of 11 invoices agreed with their printed total to the cent, which is what let us trust the 41. That is one supplier, one buyer, one year. We do not generalise it to your suppliers; vendors of AP software quote error rates of several percent of invoices, and those figures are theirs to defend.

Against that, the price of the check. A chat plan at €0 to €23 a month costs nothing extra if you already pay for it, plus the twenty minutes per invoice to upload, ask, read and file the answer, and the discipline to do it every time. Our Standard plan at €29 covers 100 documents a month; documents are counted, not pages or emails, and colleagues share the one address on paid plans. If you have ten documents a month, our Free plan and a chat model are both free, and the choice is about whether you want to be the one who remembers.

There is a third case worth naming. A purchaser who already has a chat subscription and wants to compare an invoice with a price list a few times before deciding anything should do exactly that. It is the cheapest way to learn whether your suppliers drift at all, and the invoices you check by hand are the same ones you would forward later.

When to use which

• One invoice, one price list, one question: a chat model, today, free.
• An odd layout you want explained, or a question that needs a follow-up: a chat model.
• The same check on every invoice from the same suppliers, month after month, with the arithmetic proved and the price list remembered: Price Double Check, by forwarding.
• A purchase order in Sent and an invoice in Inbox, matched without an ERP: either works once; only the service does it on arrival, and it is the subject of three-way matching without an ERP.
• Photos of paper invoices, ERP integration or an approval workflow: neither. We read PDFs and spreadsheets with a text layer and reply by email; we do not approve or pay.

Forward one invoice and the price list to your own address and compare the reply with what a chat session told you about the same pair.