Use this time calculator to easily add or subtract time values. Simply input the time values in the fields provided, leaving any blank fields to be considered as 0 by default.
Leverage this time calculator to add or subtract days, hours, minutes, and seconds from a specific start date and time. The result will display the updated date and time after applying the desired time adjustment.
Use this time calculator to perform addition or subtraction of multiple time values in an expression. Valid inputs should include days (d), hours (h), minutes (m), and seconds (s), with only the + and - operators allowed. For example, a valid expression could be '5d 4h 3m 2s + 9h 8m 7s - 6m 1s + 20s'.
Time can be added or subtracted, but its calculations differ from decimal numbers. Below is a summary of common time units:
| Unit | Definition |
|---|---|
| Millennium | 1,000 years |
| Century | 100 years |
| Decade | 10 years |
| Year (average) | 365.242 days or 12 months |
| Leap year | 366 days or 12 months |
| Month | 28-31 days (depending on the month) |
| Week | 7 days |
| Day | 24 hours or 86,400 seconds |
| Hour | 60 minutes or 3,600 seconds |
| Minute | 60 seconds |
| Second | Base unit |
| Millisecond | 10-3 second |
| Microsecond | 10-6 second |
| Nanosecond | 10-9 second |
| Picosecond | 10-12 second |
The exploration of time concepts dates back to ancient civilizations. One significant contribution comes from Aristotle (384-322 BC), who described time as "a number of movement in respect of the before and after." He believed time is infinite, continuous, and dependent on motion or change, but he also raised the intriguing notion that time’s existence might be questionable, given it is framed by two forms of non-existence: the past and future.
Aristotle’s foundational ideas have sparked ongoing debates throughout history, setting the stage for further inquiries into the nature of time.
Two influential figures in the philosophy of time are Isaac Newton and Gottfried Leibniz. Their opposing theories formed the basis of many subsequent discussions on the nature of time.
| Philosopher | Perspective |
|---|---|
| Isaac Newton | Proposed absolute time, a concept flowing uniformly regardless of external influences. He introduced "duration" as a mathematical construct, emphasizing its imperceptibility to human senses. |
| Gottfried Leibniz | Advocated for relational time, asserting it exists only through interactions between objects. According to him, time is a comparative concept used to sequence events and experiences. |
Newton's famous bucket argument further demonstrated his belief in absolute space, a concept Leibniz critiqued but failed to dismantle entirely during his lifetime.
Albert Einstein revolutionized the understanding of time with his theory of relativity, connecting space and time into a unified concept of spacetime. His work refuted Newton's view of absolute time, introducing time dilation, where time slows for objects traveling near the speed of light relative to stationary observers.
Einstein’s ideas extended to resolving Newton's bucket argument through general relativity, which explains motion using geodesics in curved spacetime rather than absolute space.
Modern time measurement relies on two primary tools: calendars and clocks. Both stem from the ancient sexagesimal system (base 60), which originated in Sumer and was refined by the Babylonians for its mathematical efficiency. This system simplifies fractional calculations and remains integral to timekeeping.
| Innovation | Details |
|---|---|
| 24-Hour Day | Originated with Egyptian sundials, dividing day and night into 12 parts each, later standardized by Hipparchus. |
| Minutes & Seconds | Derived from Hipparchus’s division of circles into degrees, evolving into time subdivisions used today. |
| Gregorian Calendar | Introduced in 1582 to correct discrepancies in the Julian calendar, aligning dates with astronomical events. |