Days Since Date Calculator
Use our days since calculator to find the number of days that have passed since a previous date.
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Joe is the creator of Inch Calculator and has over 20 years of experience in engineering and construction. He holds several degrees and certifications.
How to Calculate How Many Days Have Passed Since a Date
Calculating the number of days that have passed since a prior date can be useful for various tasks in planning, finance, or logistics. You might want to determine how many days have passed since a specific event, such as the start of a project, a significant anniversary, or the beginning of a new year.
There are a few different methods to calculate the number of days since a prior date.
Method One: Calculate the Days Since Manually
The first method involves manually calculating the number of days between two dates using a calendar.
If the dates are in the same month, you can simply subtract the day of the month of the first date from that of the second. For example, the number of days between March 3rd and March 22nd is 22 – 3 = 19 days.
However, if the dates are in different months or years, then you’ll need to follow a few steps to calculate the number of days in between. Follow these steps to find the number of days between two dates:
Step One: Break Down the Start and End Dates
Identify the day, month, and year for the start and end dates.
Step Two: Calculate the Number of Days in the End Month
Use the date of the end month as the number of days in the end month.
For instance, if the end date is September 25, then there are 25 days in the end month to add to the total number of days.
Step Three: Calculate the Number of Days in the Start Month
Subtract the starting day from the total days in the first month.
For instance, if the start date is July 15 and the end date is after July 31, there are 31 – 15 = 16 days left in July to add to the total number of days.
Step Four: Find the Days in Full Months In Between
If there are any full months between your start and end dates, add the number of days in each full month to the total number of days.
For instance, if the date range is from July 15 to September 25, then you’ll need to add all the days of August to the number of days calculated in steps two and three.
Step Five: Calculate the Total Number of Days
The final step is to add up the days from steps two, three, and four to calculate the total number of days between the two dates.
You can use also this process to find the number of days until a future date.
Method Two: Use a Spreadsheet
You can also use spreadsheet software such as Microsoft Excel to calculate the number of days since a prior date as well.
Both Google Sheets and Microsoft Excel support the DAYS function. The DAYS function takes the start and end dates as parameters, and displays the time since the start date in days.
Use the following formula in a cell to find the number of days since a date:
DAYS(end_date, start_date)
Substitute your start and end dates for the end_date and start_date parameters in the formula above.
Method Three: Use Inch Calculator
Of course, the easiest way to find the number of days since another date is to use a tool such as our day counter or duration calculator. These quickly find the number of days since a date and don’t require any special software.