Show HN: WatchPennies: An Interactive Map to Compare Cost of Living by US County

Hi everyone! I’d like to share a web app I built called WatchPennies. Initially what started as a simple question to find the disparity of costs between locations turned into a full project. It helps you compare the annual cost-of-living in different US counties side-by-side.

Unlike typical COL calculators that only compare two cities, this map lets you select as many counties as you want and see a breakdown of costs for: housing, food, transportation, healthcare, taxes, all updated live on the map. You can click counties or search by name, and the comparison chart updates instantly.

The data comes from the Economic Policy Institute’s 2025 Family Budget dataset.

Feedback is appreciated! Thank you!