# How to Use: Time Duration Calculator

The Time Duration Calculator finds the number of days, hours, minutes, and seconds between 2 given points in time.

## Getting Started with Your Calculation

1. First enter the Start Date and End Date, including a time of day for each.
• For the dates, you can use the input fields, click on the calendar icon to select your date, or click on the Today link to get today's date.
• For the time of day, use the input fields, click on Now to use the current time of day, on Start of Day for midnight (00:00 or 12:00 am), or on Noon for midday (12:00 or 12:00 pm).
2. Then click Calculate Duration to get your result.

### Remove the time

If you don't want to enter a time of day, click on Remove the time, which takes you to the Date Duration Calculator.

The Add time zone conversion link takes you to the Time Zone Duration Calculator where you can calculate the duration between a point in time in one time zone and a different point in time in another time zone.

### Remove holidays and weekends

The Count only workdays link takes you to the Business Days Calculator where you can exclude different days, like weekends and public holidays.

### Why are the years and months wrong?

The calculator adds or subtracts the larger time units before the smaller time units. This means that it adds years, then months, then days. Although the total number of days in January (31) and February (28) are different, both are counted as 1 month. In some cases, this method can lead to unexpected results.

For example, in a common year, the time span between January 28 and March 1 is calculated as 1 month and 1 day (January 28 + 1 month = February 28; February 28 + 1 day = March 1).

However, the time span between January 31 and March 1 is also shown as 1 month and 1 day. The calculator first adds 1 month to jump from January to February. But since February only has 28 days in a common year, it lands on February 28 before adding 1 day to arrive at March 1.

This may seem illogical at first, but the structure of our calendar means that there is no perfect way of calculating dates including months and years.

### Does the calculator include leap years?

Yes, all our calculators account for leap years.

### Does the calculator include leap seconds?

No, this calculator does not account for leap seconds.

### Does the calculator account for Daylight Saving Time (DST) clock changes?

No, this calculator does not take DST changes into account.

### Does the calculator include Daylight Saving Time (DST)?

The Time Duration Calculator does not allow for this. For Daylight Saving Time (DST) to be taken into account, you have to specify a location using the Time Zone Duration Calculator.

### Why are the date fields in the wrong order?

You can change the order of the Day, Month, and Year fields by selecting a different Short Date format in My Units.

### Can I edit my calculation?

To edit your calculation, scroll up to the top of the page, make your changes, and calculate again. The Make adjustment and calculate again is a shortcut to the top of the page.

### Why does the result show the wrong days of the week?

This is most likely not an error but due to the fact that the Julian calendar was still in use in the year you entered. This calendar system was eventually replaced by today's Gregorian calendar, but the date this change happened differed from one country to another.

The calculator uses the Julian-Gregorian switch date of the country you select in the settings under My Units.

### How does your algorithm work? Can you help me program my own?

We are a small team with very extensive websites to manage, so, unfortunately, we do not have the capacity to share detailed information about our algorithms or provide programming help.

### What kinds of date calculators do you offer?

1. Calculating the duration between 2 points in time: