Same Product, Different Names: How Receipt Matching Works

To follow the price of a product over time, you first have to know that two receipt lines are the same product. That sounds trivial until you look at real receipts. The same pack of pasta can appear as “SPAGHETTI 500G”, “SPAGHETTI NO5 500 G” and “SPAG.500GR” depending on the chain, the till system, or just the month.

Why receipt names are messy

Receipt lines are written for tills, not for people:

• Abbreviations. Limited width means “CHOC MLK 100G” instead of the product’s real name.
• Different systems per chain. Each chain names products its own way.
• Changes over time. A store updates its product file and the same item gets a new line text.
• Similar but different products. “MILK 1L 3%” and “MILK 1L 1.5%” differ by one character and are not the same product.

A price history built on raw line text would split one product into several and, worse, could merge two different products into one.

The raw line never changes

Whatever matching decides, the original text of each receipt line stays exactly as it was read. Matching only adds a link from that line to a product. That means a wrong link can always be fixed without losing anything from the receipt itself.

How matching works, step by step

Tasarruf works through a sequence of checks, from the most certain to the least:

1. Per store chain. Line texts are matched within a chain, because each chain has its own naming. “SPAG.500GR” at one chain says nothing about what that text means at another.
2. Known match first. If you have already confirmed that a line text at this chain is a certain product, every future line with that text at that chain is linked to it directly.
3. Hard blocks. Some differences rule out a match no matter how similar the text looks: a different size (500 g vs 1 kg), a different brand, or conflicting attributes (full-fat vs low-fat). These are never linked automatically.
4. Similarity. For the remaining candidates, the line text is compared with known products. A very close match is linked automatically.
5. Ask when unsure. In the grey zone, where the text is similar but not similar enough to be sure, Tasarruf asks you: “Is this the same product?”
6. New product. If nothing comes close, the line becomes a new product.

Why it asks you

It would be easy to link everything that looks roughly alike. It would also be wrong often enough to ruin your price history. A single bad link, such as a 1 kg pack merged with a 500 g pack, makes the unit price look like it halved or doubled overnight.

Asking costs you one tap. Your answer then applies to that line text at that chain from then on, so the same question does not come back every week. Over time, most of your regular products are matched without asking at all.

Fixing mistakes: split and merge

Sometimes a match is wrong, or two products that should be one end up separate. Matches can be changed later:

• Split a product when two different things were linked together.
• Merge two products that are really the same.

When you do, the price history is recomputed, so charts, first and last prices and unit prices reflect the corrected links.

Why matching matters for everything else

Almost every useful number in a price tracker depends on matching:

Feature	Needs matching because…
Price history and chart	it follows one product across receipts
Price change cards after saving	they compare with earlier prices of the same product
Unit price over time and shrinkflation	different pack sizes must never be blended together
Personal basket index	only confirmed or high-confidence matches count

That last point is deliberate. The personal basket index uses only matches you confirmed or that are very likely to be right, so a doubtful guess never moves your figure. For more on why pack size changes matter, see shrinkflation.

How Tasarruf helps

Tasarruf links the many ways a receipt can print a product to one product per chain, blocks matches when size, brand or attributes conflict, and asks you only when it is not sure. You can split and merge products at any time, and the price history follows. The result is a price history you can trust. Discover Tasarruf.