Time Calculator
Please enter the time values; hours, minutes and seconds to add or subtract time.
Our Time Calculator can help you determine the number of hours and minutes between times.
How to Use Our Time Calculator
- Enter your starting time. In the top row, enter your starting time, including hours, minutes, and seconds. If you don’t have any of these values, you can leave them set to zero.
- Decide if you’d like to add or subtract the difference between times. Adding between times means that the two times you enter will be added together to tell you the total time. Subtracting between times means the difference between the times will be calculated. The subtract function can thus be used to find the amount of time between two set times, i.e. the time between 5:32 pm and 7:47 pm.
- Add your ending time. In the bottom row, enter your ending time.
- Click the red ‘calculate’ button. Once you have entered all the necessary information, click ‘calculate.’
Time Conversion Table
Sometimes, we might want to know how many minutes or seconds are in a set number of hours or days. Here is a conversion table to help you calculate those values:
| 1 day | 24 hours |
| 1 day | 1,440 minutes |
| 1 day | 86,400 seconds |
| 1 hour | 0.417 days |
| 1 hour | 60 minutes |
| 1 hour | 3600 seconds |
| 1 minute | 0.00027 days |
| 1 minute | 0.017 hours |
| 1 minute | 60 seconds |
Evolution of the 24-Hour Day
Like many modern technologies, the 24-hour day has its roots in Ancient Egypt. Egyptians divided the daylight hours into ten hours, with an additional two twilight hours each day. Then night was divided into twelve hours. The twelve-hour night, and twelve-hour day, came from Ancient Egyptian observations of the stars, which they divided into thirty-six sections called ‘decans’. Ancient Egyptians were able to track the passage of time by observing these decans.
Because of the unique Egyptian system of designating separate daytime and nighttime hours, the length of an hour actually changed over the seasons, with daytime hours stretching much longer in the summer and much shorter in the winter, and nighttime hours being longer during the winter and shorter during the summer. We adopted our steady, 60-minute hour from the Ancient Babylonians, who had a predilection for the number 360. They split the year into 360 days and the day into 360 parts. But it was their division of the hour into 60 minutes that has carried on to modern time. Later, the minute was made to contain sixty seconds for neatness’ sake, to parallel the number of minutes in an hour.
Early Clocks and Other Timekeeping Devices
Humans have been keeping time for thousands of years. Egyptian obelisks are some of the earliest time-keeping devices, and were built as early as 3500 B.C. Part of a sub-group of timekeeping devices called ‘shadow-clocks’, these obelisks worked by casting a shadow which moved throughout the day. People learned what the shadow looked like at different times — for instance, that it would almost disappear each day at noon — and so could estimate the time by the appearance of the shadow.
Later, the first water-clocks were invented around 1500 B.C. Also created in Egypt, water clocks measured time by using a steady inflow or outflow of water from a basin. This basin was marked at regular intervals so that one could estimate the passage of time. In many ways, waterclocks are similar to hourglasses, though hourglasses weren’t developed for thousands of years.
Many different timekeeping devices were used over the years, including astrolabes and candle clocks, before the modern mechanical clock was developed around the start of the 14th century in Europe. These clocks required significant maintenance, but were more exact than previous timekeeping methods and also very easy to read, benefits which helped the clocks spread across the continent and, eventually, the world. Now, the most common clock is the digital clock, which was invented in the 1950s in the United States.
Feedback on the Time Calculator
What do you think about our Time Calculator? Did this tool help you figure out the days between dates? Are there other features you’d like to see added? We’d love to hear from you! Click the ‘feedback’ button to share your suggestions. If you're interested in other calculator tools, try our Days Between Dates Calculator, which can help you determine the total time between any two dates. Additionally, we have a Business Days Calculator, to help you determine the number of business days between dates.