How we calculate these numbers

Store ad prices

Weekly from USDA Agricultural Marketing Service grocery feature reports, which record the prices supermarkets advertise in their weekly ads. For each item we average the advertised prices, weighted by the number of stores USDA reports running each one. These are sale prices, so they run below what you pay on a normal week, and they aren't the price at any particular store. USDA's store counts are summed across qualifying ads, so a store running two qualifying ads may count twice, and many stores can share one chain's ad.

Comparisons

• vs the week before: only when USDA reported the item for the previous week; otherwise we show no weekly change.
• vs a year earlier: the average of the last 4 weekly reports compared with the same 4 weeks 52 weeks earlier, shown with both date ranges. Needs at least 3 of the 4 weeks on each side.
• Regions: a region with no ad this week keeps its page and shows its last reported price, marked as such.

BLS prices

Monthly national average retail prices from the US Bureau of Labor Statistics, released around the middle of the following month. They include both sale and regular prices, so they aren't a clean "shelf price", and some don't match our items exactly (each item page says how close the match is).

Experimental signals

We test whether wholesale prices (USDA mandatory price reports: pork cutout and bellies, Choice boxed beef) help predict the direction of the BLS price a month or two later. The model making the live call on an item page is the same one whose historical record we publish. The record is a historical backtest that refits on earlier months only, not a record of calls made in real time. The signals were chosen after looking at the full history, so treat them as exploratory and not as shopping advice. Every signal we've tested, with full records.

Checks

Every update runs automatic checks against USDA's own published figures, the regions and BLS prices. An update with a failing publication check isn't published. See the checks and their latest results.

Downloads and reuse

Every item page links to CSV downloads (weekly US and regional prices; monthly ad and BLS prices) and an embeddable chart. The weekly brief is written to be reused. Please link back when you use them.

Updates

We check for new reports every 30 minutes and publish them as soon as they're out: USDA's ad reports come out weekly on Fridays, BLS prices monthly. If the data stops updating, pages show a notice. Last update: 2026-10-27 15:22.