PriceProof 30 records every variant's price as it changes, then finds the lowest price actually in effect over the last 30 days. That includes a price set before the window opened and still running inside it — the case simpler tools get wrong. The figure appears under your price through a theme app block, so there is no theme code to edit. Every variant keeps its own history, so switching size or colour updates the number. Converted currencies are handled. No customer data is stored.

• Records every price change automatically, variant by variant
• Shows the 30-day low on the product page using a theme app block
• Recalculates daily as the 30-day window moves forward
• Switching size or colour shows that variant's own history

Themes show a price per kilo or litre only where the package size has been filled in, and filling it in one variant at a time is the part nobody does. UnitProof reads the size your catalog already states — a variant option, a title, a shipping weight — and says which clue it used. Nothing is written until you have seen it row by row, before and after. Every run is recorded and can be rolled back. The value goes into the native unit price fields, so your theme displays it with no edit.

• Scan the catalog and see a proposed measurement for every variant
• Preview each bulk change row by row, before and after, then apply
• Roll back any run, with the replaced values kept