Methods & Data
Method. We take eleven CPI category indexes (NSA, straight from BLS) and their official weights (BLS relative importance, December 2025, to one decimal). Move a slider and your rate becomes the weight-normalized average of category year-over-year inflation. Presets shift weight the way real budgets do: renters carry rent instead of owners' equivalent rent; retirees carry roughly double the medical weight; heavy drivers carry more transportation.
Data notes. A weighted average of category year-over-year rates approximates, but does not replicate, the BLS Laspeyres aggregation. Categories are national averages, so prices where you live can differ. The weights you choose are shares of spending and are normalized to sum to 100%.
Data: CPI-U category indexes via BLS; headline CUUR0000SA0.
Full formulas, glossary, and data sources: Methods & Data.
Calculations used: #1 Year-over-year (YoY) inflation rate, #39 Personal CPI reweighting (user-weighted Laspeyres).
Data sources: FRED (Federal Reserve Bank of St. Louis); U.S. Bureau of Labor Statistics.
Disclaimers
This is an illustrative prototype, not a quote. Your rate is a weight-normalized average of category rates at national-average prices, which approximates but does not replicate the BLS Laspeyres aggregation. The inflation rates shown are not your literal cost of living.
This product uses the FRED® API but is not endorsed or certified by the Federal Reserve Bank of St. Louis. BLS.gov cannot vouch for the data or analyses derived from these data after the data have been retrieved from BLS.gov.
Not a forecast by F/m. Not investment advice. This tool is provided for informational and educational purposes only. It is not a recommendation to buy or sell any security or to pursue any investment strategy. Data is believed reliable but is not guaranteed. F/m Investments, LLC is an investment adviser registered with the SEC; registration does not constitute an endorsement nor indicate any particular level of skill or ability. © 2026 F/m Investments LLC.
