Add or subtract time values, dates, or expressions with unit support.
Complete time utility to add or subtract time values, calculate new dates given a duration, or evaluate complex time-unit expressions.
| Unit | Definition |
|---|---|
| millennium | 1,000 years |
| century | 100 years |
| decade | 10 years |
| year (average) | 365.242 days or 12 months |
| common year | 365 days or 12 months |
| leap year | 366 days or 12 months |
| quarter | 3 months |
| month | 28-31 days |
| week | 7 days |
| day | 24 hours or 1,440 minutes |
| hour | 60 minutes or 3,600 seconds |
| minute | 60 seconds |
| second | base unit |
Ancient Greece (Aristotle): Aristotle defined time as "a number of movement in respect of the before and after." Essentially, Aristotle's view of time defined it as a measurement of change requiring motion or change.
Newton vs. Leibniz: Isaac Newton argued for "absolute time" that flows without regard to external factors. In contrast, Leibniz believed time is a relational concept that only makes sense in the presence of objects to sequence events.
Einstein: Albert Einstein introduced the idea of spacetime. He posited that the speed of light is constant for all observers, meaning time itself must change for observers at different relative velocities.
Measurements of time are based on the sexagesimal system (base 60), originating from ancient Sumer and later adopted by Babylonians. Base 60 is used because 60 is a superior highly composite number with 12 factors, simplifying fractions.
Early devices ranging from oil lamps and clepsydras (water clocks) to mechanical pendulum clocks and current atomic clocks show our progress. Atomic clocks, using cesium resonance, are the most accurate, defining the SI unit of the second.
Time is calculated using 60-base math (1m=60s, 1h=60m, 1d=24h).Time calculation is unique because it doesn't use the standard base-10 system we use for money or distance. Instead, it uses a complex mix of Base-60 (Sexagesimal) and Base-24.
Because years, months, and days are based on the rotation of the Earth and its orbit around the Sun, they don't fit into neat decimal numbers. This is why we have leap years every four years—to "catch up" the 0.242 days that the Earth takes to complete an orbit beyond the flat 365 days.
Our Expression mode allows you to treat time like a mathematical formula. This is particularly useful for project management, video editing, or calculating long-distance flight durations across multiple layovers.
Example: 1d 12h + 12h = 2d 0h 0m 0s