Convert Excel Time to Decimal

Dates and Times Explained

Excel’s unit of time is ‘days’ and it’s used to represent dates and time.

For example, I’m writing this at

• 11:41 on Monday 11th September 2023

in Excel that date and time is stored as the number

• 45180.48681

The integer part of that number (45180) represents the date and is the number of days since the 01/01/1900.

The decimal part (0.48681) is the time and is how far through the day we are. By the time I finish writing this, it will probably be mid-day and in Excel that will be the number 0.5 as it is exactly half way through the 24 hour day. This also means that 6:00am will be 0.25 (quarter of the day) and 6:00pm will be 0.75 (three quarters of the day).

If you remember that Excel stores dates and times in days, then you won’t go far wrong with any date/time calculations.

Convert to Decimal and Back Again

Now to answer the question ‘how do I convert time to a decimal value in Excel’, all we have to know is that every day contains 24 hours. As such multiplying an Excel time by 24 will result in the equivalent decimal value.

For example, 3 ? hours in Excel appears in a cell as 3:30 and the underlying number is 0.145833333. If we multiply this number by 24 we get 3.5.

The same is true going the other way, if we have a time of 3.5 hours and want that in Excel’s native time format, we can divide by 24.

Often the data arrives in Excel after being exported from another system, and now it doesn't matter which format it exports in as we can convert very simply between the two.

If you have a date or time related question, drop me a message and I'll try to help.