About

TheCashTracker is a free hobby project for following US currency as it changes hands across the country. Every paper bill carries an eleven-character serial number — log it once and wait. When somebody else, somewhere else, enters the same serial, you'll see where the bill ended up and how far it traveled to get there.

How to find a serial number

On any US bill, the serial number appears twice on the front — once near the upper right and once near the lower left. It starts with one or two letters, then eight digits, then one letter. Just type the whole thing in, no spaces needed.

What we track

• Serial number, ZIP code, and date for each sighting.
• Distance and time between sightings, calculated automatically.
• An optional note (where you got it, anything fun).

What we don't track

Real street addresses, names of people you got bills from, or anything you didn't type in. It's a fun map, not surveillance.