A Time Calculator is a tool that helps you quickly add or subtract time values, usually expressed in hours, minutes, and seconds. It is very useful for scheduling, time management, work tracking, or calculating the difference between two events.
Add or subtract time from any given starting date and time. Enter values in days, hours, minutes, and seconds.
Enter multiple time values with units (d = days, h = hours, m = minutes, s = seconds) and use + or – to add or subtract them. Example: "1d 2h + 30m – 45s".
Early timekeeping devices were the first tools humans developed to measure and track time before mechanical clocks were invented. They were based on natural phenomena like the movement of the sun, flow of water, or burning of materials.
One of the oldest timekeeping devices. Worked by using the position of the sun's shadow cast by a stick (called a gnomon) on a flat marked surface. Accurate only during the daytime and depended on weather and season.
Used by ancient Egyptians, Greeks, and Chinese. Measured time by the steady flow of water from or into a container. Could be used day and night, but required regular monitoring and refilling.
Time measured by the rate at which a candle burned. Marks were made on the candle to indicate hours. Useful indoors but influenced by drafts or varying wax quality.
Calculate total hours worked, overtime, and breaks for payroll and scheduling.
Determine arrival times across different time zones and account for travel duration.
Add up task durations and calculate project deadlines and milestones.