UK Online Shelf-Price Index

Posted online shelf prices, not prices paid. Not a CPI and not a government statistic. Independent: not affiliated with, endorsed by or sponsored by Tesco, Sainsbury's, Asda or Aldi. This version is vintage 2026-W43, revision 1: the first change week of the current series (base 2026-W42 = 100). The all-products headline was 99.9645 (-0.0355% week on week) and food and soft drinks 100.0195 (+0.0195%), from 74,503 products matched in both weeks, with all four retailers in the headline. The four-week change starts at 2026-W46. No index was produced for 2026-W41; the closed first series (base 2026-W39) is a separate record, and levels in the two series cannot be compared. Methodology note for 2026-W43: in the 2026-W42 Aldi snapshot, 1,263 products that were in both weeks had no pack size and no unit price; the cause is not known. A pack size missing in one of the two weeks is treated as unknown, not as a change, so these products are compared on their shelf price. Under the earlier rule, which left them out, Aldi's 2026-W43 level would have been 99.8128 instead of 99.8622 and the headline 99.9522 instead of 99.9645. A smaller pack at the same shelf price in such a week may not be shown. The full note is on the method page. `matched` counts products found in both weeks before any are left out, and `matchedShare` can be above 1 when products move into a class between the weeks. The index follows the posted online shelf prices of the same products at Tesco, Sainsbury's, Asda and Aldi in the UK from one week to the next, matched on each retailer's own product id in weekly snapshots of the retailers' websites. Within each retailer and product class the weekly change is a Jevons index (equal product weights); the all-products headline weights the four retailers equally. There are no spending weights. Currency: GBP. The files hold index numbers and counts only (level, week-on-week and four-week change, matched counts and share, status), keyed by retailer and product class: no product names, prices, product ids, images or URLs. Method and data dictionary: https://data.yappman.com/shelf-price-index/method/ . Each version of this record is one dated vintage. Published vintages are kept as first published; a correction would be published as a new, clearly marked revision. Added 27 October 2026: product-level shelf prices on request (Tesco, Sainsbury's, Asda and Aldi) are available from a pay-per-event Actor on the Apify Store, charged to the Apify account that runs it: https://apify.com/yappman/uk-supermarket-price-scraper