This calculator allows you to "add" or "subtract" two-time values. Input fields can be left blank, and they will be treated as 0 by default.
Add or subtract time from a date.
This calculator allows you to add or subtract time (days, hours, minutes, and seconds) from a given starting time and date. The new time and date will be determined by the amount of time deducted or added. The Time Duration Calculator can be used to compute the time difference (days, hours, minutes, and seconds) between two different dates.
This calculator allows you to add or subtract two or more time values in the form of an expression. An acceptable input has the letters d, h, m, and s after each value, where d represents days, h represents hours, m represents minutes, and s represents seconds. The only accepted operators are + and -. "1d 2h 3m 4s + 4h 5s - 2030s" is a valid phrase.
Time can be added or removed, just like any other quantity. However, due to the way time is defined, calculations must be computed differently than decimal values. The table below displays some typical units of time.
Throughout human history, philosophers and scientists have proposed numerous definitions of time. The ancient Greek philosopher Aristotle (384-322 BC) gave one of the older perspectives, defining time as "a number of movements in respect of the before and after." Essentially, Aristotle defined time as a measure of change that necessitated the presence of motion or change. He also believed that time was limitless and continuous and that the universe had always existed and would continue to exist. Interestingly, he was also one of the first, if not the first, to propose that the existence of two separate types of non-existence calls the existence of time into doubt. Aristotle's perspective is only one of many in the debate over time, the most contentious of which began with Sir Isaac Newton and Gottfried Leibniz.
Newton's Philosophiae Naturalis Principia Mathematica addressed the concepts of space and time as absolute. He contended that absolute time exists and flows without regard for external causes, referring to it as "duration." Absolute time, Newton argues, can only be grasped mathematically because it is imperceptible. Relative time, on the other hand, is what humans perceive and is a measurement of "duration" based on the motion of things like the sun and moon. Newton's realist perspective is commonly known as Newtonian time.
Contrary to Newton's arguments, Leibniz believed that time only makes sense when it interacts with other objects. According to Leibniz, time is simply a concept, like space and numbers, that allows humans to compare and sequence events. This reasoning, known as relational time, does not allow time to be quantified. It is essentially the subjective perception and sequencing of objects, events, and experiences acquired during a lifetime.
The bucket argument, sometimes known as Newton's bucket, is one of the most well-known arguments to emerge from the communication between Newton's spokesman Samuel Clarke and Leibniz. In this argument, water in a bucket suspended from a rope has a flat surface that becomes concave as the water and bucket rotate. If the bucket's rotation is then stopped, the water remains concave as it continues to spin. Because this example demonstrated that the concavity of the water was not caused by an interaction between the bucket and the water, Newton concluded that the water was rotating with respect to a third entity, absolute space. He contended that absolute space was required to account for situations in which a relational viewpoint could not adequately explain an object's rotation and acceleration. Despite Leibniz's efforts, the Newtonian idea of physics persisted for almost two decades.
While many scientists, including Ernst Mach, Albert A. Michelson, Hendrik Lorentz, and Henri Poincare, helped to shape theoretical physics and astronomy, Albert Einstein is credited with compiling and describing the theory of relativity and the Lorentz Transformation. Unlike Newton, who believed that time progressed in the same way for all observers regardless of frame of reference, Einstein, drawing on Leibniz's perspective that time is relative, presented the concept of spacetime as related rather than independent ideas of space and time. Einstein proposed that the speed of light, c, in vacuum, is constant for all observers, regardless of the velocity of the light source, and that distances observed in space are proportional to distances measured in time. Essentially, for observers in distinct inertial frames of reference (different relative velocities), the structure of space and the measurement of time change at the exact moment due to the invariance of the speed of light - a viewpoint that differs significantly from Newton's. A spaceship traveling at near-lightspeed is a typical illustration of this. To an observer on another spaceship flying at a different speed, time would flow slower on the spacecraft, traveling near the speed of light, and it would hypothetically stop if the spacecraft reached the speed of light.
Said another way that if an object moves faster through space, it moves slower through time, and vice versa. This must occur for the speed of light to be constant.
It is worth noting that, some two centuries later, Einstein's theory of general relativity provided a solution to Newton's bucket argument. In general relativity, an inertial frame of reference follows a geodesic of spacetime, which generalizes the concept of a straight line to curved spacetime. According to general relativity, an object moving against geodesic experiences a force; an object in free fall does not experience a force because it is following a geodesic; and an object on Earth experiences a force because the planet's surface exerts a force against the geodesic to hold the object in place. As a result, rather than revolving in "absolute space" or in relation to distant stars (as proposed by Ernst Mach), the water in the bucket is concave because it rotates in relation to a geodesic.
The numerous notions of time that have prevailed throughout history demonstrate that even the most well-conceived theories can be challenged. Despite all of the achievements in quantum physics and other fields of science, time still needs to be understood entirely. It may only be a matter of time before Einstein's absolute constant of light is overturned, allowing humanity to go back in time!
The calendar and the clock are the two most used methods of determining time nowadays. These time metrics are based on the sexagesimal number system, with 60 as its foundation. This system originated in ancient Sumer in the third millennium BC and was adopted by the Babylonians. It is presently used in a modified form to measure time, angles, and geographical coordinates. Base 60 is utilized because the number 60 is a superior, highly composite number with twelve factors. A superior, extremely composite number is a natural number with more divisors than any other number when scaled to a power of itself. With so many factors, the number 60 simplifies many sexagesimal fractions, and its mathematical advantage is one of the reasons it is still used today. For example, 1 hour, or 60 minutes, can be split evenly into 30, 20, 15, 12, 10, 6, 5, 4, 3, 2, and 1 minute, demonstrating why the sexagesimal method is used to measure time.
The Egyptian civilization is credited with being the first to divide the day into smaller sections through the use of sundials, leading to the development of the second, minute, and 24-hour notion. The first sundials divided the time between sunrise and sunset into twelve segments. Because sundials could not be used after sunset, determining the passage of night was more difficult. However, Egyptian astronomers observed patterns in a group of stars and used 12 of them to construct 12 divisions of night. One hypothesis explains how the concept of a 24-hour day came about by dividing the day and night into two 12-part divisions. The Egyptian divisions, however, fluctuated according to the time of year, with summer hours being significantly longer than those of winter. It was not until later, around 147 to 127 BC, that a Greek astronomer named Hipparchus recommended dividing the day into 12 hours of daylight and 12 hours of darkness based on equinox days. This created the 24 hours known as equinoctial hours, which resulted in days with equal lengths of hours. Despite this, fixed-length hours only became widespread in the 14th century, coinciding with the introduction of mechanical clocks.
Hipparchus also created a system of longitude lines that covered 360 degrees, which Claudius Ptolemy later divided into 360 degrees of latitude and longitude. Each degree was divided into 60 parts, which were further divided into 60 smaller pieces known as the minute and second, respectively.
While diverse civilizations produced many other calendar systems over time, the Gregorian calendar is the one that is most widely used around the world. It was established by Pope Gregory XIII in 1582 and is primarily based on the Julian calendar, a Roman solar calendar suggested by Julius Caesar in 45 BC. The Julian calendar needed to be corrected, allowing the astronomical equinoxes and solstices to overtake it by about 11 minutes per year. The Gregorian calendar significantly improved on this issue. For more information on the Gregorian calendar's history, please see the date calculator.
Early timekeeping systems varied by culture and locale, with the goal of dividing the day or night into distinct hours for work or religious rites. Some of them include oil lamps and candle clocks, which were used to indicate the passage of time from one event to the next rather than telling the time of day. The water clock, also known as a clepsydra, was the most accurate in the ancient world. Clepsydras function by regulating the flow of water from or into a container, which is then measured to calculate the passage of time. Hourglasses, also known as sandglasses, first debuted in the 14th century and were intended to serve the same purpose as oil lamps and candle clocks. Eventually, when clocks improved in accuracy, they were used to calibrate hourglasses to measure specific periods.
In 1656, Christiaan Huygens invented the first pendulum mechanical clock, which was regulated by a mechanism with a "natural" period of oscillation. Huygens was able to refine his pendulum clock to produce errors of less than 10 seconds every day. Atomic clocks, on the other hand, are the most accurate timekeeping systems available today. Atomic clocks maintain track of time using an electrical oscillator based on caesium nuclear resonance. Different types of atomic clocks exist, but caesium clocks are the most common and precise. The second, the SI unit of time, is calibrated by measuring the periods of radiation from a caesium atom.