The methodology and data on this site is presented as accurately as I can, but I'm not a statistician and errors may exist. Please do not rely on this data to make policy, make life alerting decisions, or similar.
All data on this site comes from either the Consumer Price Index or Producer Price Index calculated by the Bureau of Labor Statistics. Data is released on all products Monthly, and we collect data periodically once it is released.
The data is a Price Index, which means it's a normalized sample of prices for a given product. A specific product is not tracked, but a group of products is tracked and weighted by smart people. The value of the index does not represent the exact price that is paid, rather the relative cost compared to a fixed point in time in the past.
The bottom line, though, is that when a price index increases 10%, the average price of that product has also increased 10%.
When looking at prices for a specific date range, we calculate the percent change from the average index value of all product at the start vs at the end.
For the overall pages (pages that aren't looking at a specific event), we look at the last 6 months of data. Keep in mind that due to the somewhat delayed nature of how the data is released, it may be slightly longer than 6 months.
For events, we look at either the last 6 months of data or the calendar year. In all cases, the start date or length of time is shown next to each figure.
No, the BLS releases data once per month, usually around the middle of the month for the last calendar month. For example, November's data is released in Mid-December. The data is also subject to revision for 4 months after it's release, and we'll update our site should the data be updated.
This site isn't run by an economist, so inaccuracies (though not intentional) may exist in the calculations or methodology. The data, though provided by the BLS, can also be inaccurate nor can the BLS verify the data once it's stored elsewhere.
Should you want to, we share the BLS series ID(s) for each product. You can download this raw data from the BLS directly to validate the data.
It should go without saying, but this website is presented in a good-faith effort to highlight prices, but it's accuracy cannot be absolutely ensured. Errors may exist, data may be old and not fully updated, or other issues may cause the values on the site to not be accurate.
Do not rely on this site to make purchase decisions, investments, other other important decisions.
No, for multiple reasons. The biggest being that the data is available directly from the BLS website for free, so it doesn't make sense to query a secondhand copy of this primary data. If you need this data, just go get it from the BLS.