Mastering Time Calculation in Excel: The Ultimate Formula Guide

Excel is a powerful tool that allows users to perform a wide range of calculations, including time calculations. Whether you need to track working hours, calculate project durations, or simply convert time units, Excel provides various formulas and functions to help you achieve accurate results. In this article, we will explore the most commonly used formulas for calculating hours in Excel.

Converting Time Units

Before diving into complex calculations, it’s essential to understand how Excel handles time units. In Excel, time is represented as fractions of a day. Each day is considered as 1, with 24 hours being equal to 1 day. To convert time into decimal format in Excel, you can multiply the number of hours by 24.

For example, if you have 2 hours and 30 minutes and want to convert it into decimal format, you can use the formula “=2.5*24”. This will give you the result of 60 (minutes) since 2 hours and 30 minutes is equivalent to 150 minutes.

Calculating Working Hours

One common scenario in which you might need to calculate hours in Excel is when tracking working hours for employees or projects. To calculate working hours between two specific dates and times, you can utilize the NETWORKDAYS function combined with simple arithmetic operations.

The NETWORKDAYS function calculates the number of working days between two dates while excluding weekends and specified holidays. By subtracting start and end times from each other and multiplying by the number of working days, you can obtain accurate working hour calculations.


For instance, assuming that cell A1 contains the starting date and time while cell B1 contains the ending date and time, the formula “=NETWORKDAYS(A1,B1)*8” will give you the total number of working hours between those two dates (assuming an 8-hour workday).

Calculating Duration

When working with project management or scheduling tasks, it’s often necessary to calculate the duration between two specific dates or times. Excel provides the DATEDIF function, which allows you to calculate the difference between two dates in various units, including days, months, and years.

To calculate the duration in hours between two dates and times, you can use the following formula: “=DATEDIF(start_date+start_time,end_date+end_time,”h”)”. This formula adds the start time and end time to their respective dates and calculates the difference in hours.


For example, if cell A1 contains the starting date, B1 contains the starting time, C1 contains the ending date, and D1 contains the ending time, you can use “=DATEDIF(A1+B1,C1+D1,”h”)” to get the duration in hours.

Adding and Subtracting Time

In addition to calculating durations and working hours, Excel allows you to add or subtract time from a given date or time. This can be useful when dealing with deadlines or scheduling tasks.

To add or subtract a specific amount of time from a given date or time in Excel, you can use simple arithmetic operations combined with cell references. For example, if you have a starting date and want to add 3 days and 4 hours to it, you can use “=A1+3+TIME(4,,)”.


The TIME function takes three arguments: hours, minutes (optional), and seconds (optional). In this case, we set only the hour argument as 4 since we want to add 4 hours. You can adjust these arguments according to your specific requirements.

In conclusion, mastering time calculations in Excel is essential for various tasks ranging from project management to tracking employee working hours. By understanding how Excel handles time units and utilizing formulas like NETWORKDAYS for working hour calculations or DATEDIF for duration calculations along with basic arithmetic operations, you can efficiently perform accurate time calculations in Excel.

This text was generated using a large language model, and select text has been reviewed and moderated for purposes such as readability.