A timesheet is a record of time spent on a job by an employee originally for the employer to determine the payroll. They are an old concept and used to be paper and in some cases still are. Increasingly they are software systems. Timesheets may record the start and end time of tasks, or just the duration. It may contain detailed breakdowns of tasks accomplished by the working. This information may be used for payroll, client billing, and increasingly for project costing, estimation, tracking and management.

Factory workers often have a "time card" and "punched in" by inserting their card into automatic timestamp machine when starting and ending their work shift .

Some companies provide web-based timesheet software or services that provide a means to track time for payroll, billing and project management. Sometimes this software is free[1]. This project management data can make complex cost relationships visible, thereby allowing lower costs. This knowledge can drive corporate strategy as users let their competitors perform the unprofitable work.

Time tracking can lower costs in 3 ways: by making payroll processing more efficient, by making costs visible so you can lower them, an by automating billing & invoicing.

Time tracking can increase revenue through automating billing, which tends to make it easier for a company to get correct invoices out for all hours worked by consulting staff. This speeds up payment and eliminates the hassles of 'dropping' bills.

By lowering costs in 3 ways, and increasing revenue in one way, timesheet management technologies that are web-based can improve the health of companies [2].

Some people hate timesheets, time management and they hate tracking their time. Professionals often feel this way. In some cases they do not trust their managers to use the information intelligently and fairly. In some cases it feels Orwellian to them. In some cases it seems like needless bureaucracy. If they really care about making the company improve and understand the benefits described above, then they can make their own ROI calculation and see if it's worth it.