# Time Calculator

## Calculator Use

Time calculator to perform elementary arithmetic with units of time. Add, subtract, multiply and divide units of time in days, hours, minutes and seconds using whole numbers or decimals. Use to add and subtract two units of time or, multiply and divide a time by a real number. Answers will also be provided for equivalent decimal time in each of days, hours, minutes and seconds.

## How to Calculate Time

### How to Add Time

When adding days, hours, minutes and seconds do the following.

- add up the seconds
- if the total is greater than 59 seconds, subtract 60 from seconds and carry 1 to minutes
- add up the minutes including any carried over from seconds
- if the total is greater than 59 minutes, subtract 60 from minutes and carry 1 to hours
- add up the hours including any carried over from minutes
- if the total is greater than 24 hours, subtract 24 from hours and carry 1 to days
- add up the days including any carried over from hours

#### Example adding units of time

Add 2 days 21 hours 45 minutes 39 seconds to 5 days 10 hours 45 minutes 22 seconds

- 39 seconds + 22 seconds = 61 seconds

- 61 seconds - 60 = 1 second and carry 1 minute
- 1 minute + 45 minutes + 45 minutes = 91 minutes

- 91 minutes - 60 = 31 minutes and carry 1 hour
- 1 hour + 21 hours + 10 hours = 32 hours

- 32 hours - 24 = 8 hours and carry 1 day
- 1 day + 2 days + 5 days = 8 days

- In Summary

### How to Subtract Time

When subtracting days, hours, minutes and seconds do the following.

- subtract the seconds
- if the seconds you are subtracting is greater than the top number, first borrow 1 minute from the top minutes and add 60 to the top seconds. Then subtract.
- subtract the minutes
- if the minutes you are subtracting is greater than the top number, first borrow 1 hour from the top hours and add 60 to the top minutes. Then subtract.
- subtract the hours
- if the hours you are subtracting is greater than the top number, first borrow 1 day from the top days and add 24 to the top hours. Then subtract.
- subtract the days

Note that in any case where you need to borrow, if there is nothing to borrow from the first higher unit than you must borrow from the column of the second higher unit just like you do in long subtraction with borrowing using integers and borrowing from the next place value.

#### Example subtracting units of time

Subtract 2 days 21 hours 56 minutes 18 seconds from 5 days 0 hours 10 minutes 13 seconds

- subtract seconds
- 13 seconds is less than 18 seconds so borrow 1 from minutes
- since 1 minute = 60 seconds
- add 60 seconds to 13 to get 73
- 73 seconds - 18 seconds = 55 seconds

- subtract minutes
- 9 minutes is less than 56 minutes so borrow 1 from hours
- there are 0 hours so first borrow 1 from days
- since 1 day = 24 hours and 1 hour = 60 minutes
- add 24 to hours then borrow 1 from hours to leave 23
- add 60 minutes to 9 to get 69
- 69 minutes - 56 minutes = 13 minutes

- subtract hours
- 23 hours - 21 hours = 2 hours

- subtract days
- 4 days - 2 days = 2 days

- In Summary

### How to Multiply Time

When multiplying days, hours, minutes and seconds do the following.

- multiply each unit of time by the unitless multiplier
- working on the answer from right to left, lowest to highest, convert excess units to a higher unit
- if seconds are greater than 59, divide by 60 to get a quotient and remainder
- keep the remainder as total seconds and carry the quotient and add it to minutes
- if minutes are greater than 59, divide by 60 to get a quotient and remainder
- keep the remainder as total minutes and carry the quotient and add it to hours
- if hours are greater than 23, divide by 24 to get a quotient and remainder
- keep the remainder as total hours and carry the quotient and add it to days

#### Example multiplying units of time

Multiply 2 days 10 hours 32 minutes 16 seconds by 5

- multiply each unit of time by 5

- 80 seconds is greater than 59 so convert excess to minutes
- 80 divided by 60 equals 1 with a remainder of 20
- keep 20 seconds and carry the 1 to minutes
- 160 + 1 = 161 minutes

- 161 minutes is greater than 59 so convert excess to hours
- 161 divided by 60 equals 2 with a remainder of 41
- keep 41 seconds and carry the 2 to hours
- 50 + 2 = 52 hours

- 52 hours is greater than 24 so convert excess to days
- 52 divided by 24 equals 2 with a remainder of 4
- keep 4 hours and carry the 2 to days
- 10 + 2 = 12 days

- In Summary

### How to Divide Time

When dividing days, hours, minutes and seconds do the following.

- divide each unit of time by the unitless divisor
- working on the answer from left to right, highest to lowest units, convert any decimal values to whole numbers shifting the decimal amount to a smaller time unit
- if days has a decimal part, keep the whole part as total days and convert the decimal part to hours
- since 1 day = 24 hours, multiply the decimal part by 24 and add the result to hours
- if hours has a decimal part, keep the whole part as total hours and convert the decimal part to minutes
- since 1 hour = 60 minutes, multiply the decimal part by 60 and add the result to minutes
- if minutes has a decimal part, keep the whole part as total minutes and convert the decimal part to seconds
- since 1 minute = 60 seconds, multiply the decimal part by 60 and add the result to seconds
- if second has a decimal part, you can usually leave this as your final answer depending on your application

#### Example dividing units of time

Divide 4 days 10 hours 13 minutes 16 seconds by 4

- divide each unit of time by 4

- work from right to left, highest to lowest units, to convert any decimal values to whole numbers
- hours is not a whole number so convert the decimal part to minutes
- 2.5 hours is 2 hours plus 0.5 hours
- since 1 hour = 60 minutes then 0.5 of 1 hour equals 0.5 of 60 minutes = 30 minutes
- keep the 2 hours and carry 30 to minutes
- 30 + 3.25 = 33.25 minutes

- minutes is not a whole number so convert the decimal part to seconds
- 33.25 minutes is 33 minutes plus 0.25 minutes
- since 1 minute = 60 seconds then 0.25 of 1 minute equals 0.25 of 60 seconds = 15 seconds
- keep the 33 minutes and carry 15 to seconds
- 15 + 4 = 19 seconds

- In Summary

**Cite this content, page or calculator as:**

Furey, Edward "Time Calculator"; CalculatorSoup,
*https://www.calculatorsoup.com* - Online Calculators