An expense tracker is a tool that helps individuals or businesses monitor their spending. It can be a simple spreadsheet, a mobile app, or specialized software designed to record and categorize expenses. By keeping track of where money goes, users can identify spending habits and make informed financial decisions. Many expense trackers offer features like budget setting, expense categorization, and reporting. Some popular options include Mint, YNAB (You Need A Budget), and Expensify. These tools can help users stay within their budgets, save money, and achieve their financial goals more effectively.