Add Time Calculator

A total time calculator is a tool for combining multiple times together. Each time is entered as hours, minutes and seconds and the tool combines them into a total duration, adjusting seconds, minutes and hours accordingly like a clock would. Decimal numbers are not used. The tool is useful in situations where you need to add up several times regularly, such as weekly work schedules, multiple lap times, individual song durations on a playlist or multiple services on an invoice.

To use this tool to calculate your total time, follow these steps:

Select the number of times to add. Each time is entered on a line and has the format "hours : minutes : seconds". Blank lines are treated as zero so not all fields need to be filled in. The result panel will update immediately as entries are made, showing the total duration in different formats at once.

The total time is shown as normal hours, minutes and seconds. If it exceeds a day then it will be split into days, hours, minutes and seconds. In addition there is also a value shown as a decimal for the hours, minutes and days. The "Total" option allows you to convert the same result to seconds, minutes, hours, days or weeks. The "Average" field divides the total time by the number of times entered.

The difference between calculating total time and decimal addition:

Normal numbers are added using the decimal system. If you add one to nine, it becomes ten and then starts a new place value. Time however uses sixty (seconds per minute) and twenty four (hours per day) as bases for addition. So adding 40 minutes and 30 minutes does not give 70 minutes but rather 1 hour and 10 minutes. Similarly 26 hours is not just added to 26 hours, it is converted into 1 day and 2 hours.

With manual calculations you first have to add each column and carry the excess values into the next higher unit. With a timesheet with many rows there is a risk of forgetting a carry. This tool converts every time to seconds, sums them up and then converts the sum back to standard time units, so that carries are always correct.

Manually add times in a clock format:

To add two times in the format of 1:45:30 and 2:30:45 without a calculator, first add the seconds, then the minutes, and finally the hours. Whenever a digit reaches the value of 60, it is carried over. Adding the seconds gives 75, which is equal to 1 minute and 15 seconds. So write down 15 and carry over the 1 to the minutes place. The minutes are 45 plus 30 plus the carried over 1, which equals 76. This is equivalent to 1 hour and 16 minutes, so write down 16 and carry over the 1 to the hours place. The hours are 1 plus 2 plus the carried over 1, which equals 4. So the total time is 4:16:15. Regardless of the number of input lines, this tool will automatically perform this calculation for you.

Time units:

Since total time can be expressed in various units, it is helpful to summarize the conversion relationships. Seconds are the base unit of time in the International System of Units (SI), and all subsequent higher units are fixed multiples of seconds.

Since the length of months and years on a calendar is not constant, this tool aggregates time into days, hours, minutes, and seconds, and shows days and weeks as exact values of 24 hours or 7 days respectively.

Areas of application for a tool to calculate total times:

The most typical use is for time sheets. Daily hours worked are added up to determine total weekly work hours and converted into decimal hours used in payroll calculations. Runners and swimmers can add partial or lap times together to calculate the overall time of a training session or relay race. Editors and DJs can summarize play times of clips, songs, and podcast segments to create a schedule that fits within allotted time frames. Chefs and brewers can add up individual work steps to create a timeline while hourly contractors can sum multiple service hours before issuing an invoice.

Tips for use:

Any unused rows can be left blank. As they are evaluated as a zero, you do not have to enter anything in the 0:00:00 format. The time fields also allow for numbers greater than 24 to be entered. Each entry represents an individual amount of time and not a clock time. When payroll is run please verify the decimal hours. For example, 9 hours and 30 minutes will show as 9.5. With an average card you can convert the total time into a representative single amount of time. This allows for things like average rounds or typical shift length to be determined.

This tool should be used for general planning and timekeeping purposes only. If you are using work hours for payroll, please note that your employer's rounding rules and break requirements may differ from the simple sum of minutes.