Days Calculator - Calculate the Days Between Dates

  1. Subtract months: Use this calculator to find a date in the past by subtracting months from a start date.
  2. Months between dates: Find the number of months between two dates.
  3. Add months: Use this to find a date in the future by adding months to a start date.
Input your start date and number of days to add

Using our day calculators

We built the year calculator to help quickly solve for counting years forward, backward, and between two dates. These are three separate calculations, and here’s how you'd use each:

  1. Choose the type of calculation you need: There are many ways to calculate dates by years.
    • Subtract Years is used for finding a date before the date you choose. For example: 3 years before 2024. This calculation will return 2021.
    • Years Between Dates will give you the specific number of years when choosing two dates. For example: Years between 2015 and 2024. This calculation will return 9 years.
    • Add Years counts forward from a specific date you choose. For example: 5 Years from 2019 will give you 2024.
  2. Input your date & timeline: We've made it so it won't fully calculate until you fill both dates. Please contact us if you find a bug.
  3. Evaluate your answer: Make sure the result makes sense for your query. Additionally, you can find other calculators we've built for finding years before today, years from today, years until a specific date, and years from a specific date. These will bring you directly to specific date calculators.

How to Calculate the Number of Days Between Two Dates

Calculating the number of days between two dates can be straightforward with the right tools, such as a calendar app, an online calculator, or using formulas in spreadsheet programs like Excel or Google Sheets. Here are the basic steps to manually figure out the duration in days:

  1. Identify the Start and End Dates: Write down or enter the start and end dates of the period you're interested in. Knowing the exact dates is crucial for an accurate calculation.
  2. Use a Calendar or Date Calculator: If you're doing this manually, count the days on a calendar from the start date to the end date, including the start day and excluding the end day. For a quicker solution, use an online date calculator by entering the start and end dates—it will compute the total days for you.
  3. Calculate Using a Spreadsheet: In programs like Excel or Google Sheets, you can use a simple formula to find the difference in days. For example, if the start date is in cell A1 and the end date is in cell B1, the formula =B1-A1 will give you the number of days between the two dates.

Tips for Calculating the Number of Days Between Two Dates

  1. Include the End Date: When counting the days, decide if you need to include the end date in your calculation. For continuous periods, like a rental or a subscription, including the end date might be necessary.
  2. Consider Time Zones: For events or deadlines that span different time zones, consider the impact of the time zone on the actual number of days, especially if the start and end times are critical.
  3. Be Mindful of Public Holidays: Depending on the context of your calculation, you might need to exclude public holidays or weekends if you're calculating working days or business days.

How to Subtract Days from a Date

Subtracting days from a date allows you to calculate past events or deadlines. It’s a simpler process than dealing with years, as you don’t need to worry about leap years for short-term calculations. Here's how to do it:

  1. Identify the Start Date: Determine the date from which you want to subtract days. This will be your starting point.
  2. Decide the Number of Days to Subtract: Figure out how many days you need to go back from your start date.
  3. Perform the Subtraction: Use a calendar, an online date calculator, or a simple arithmetic calculation to find the new date. For manual calculations, count the days backward from your start date.

This method is useful for finding due dates, historical events, or any past date relative to a known date.

Tips for Subtracting Days from a Date

  • Account for Month Changes: When subtracting days, crossing into a previous month or year changes the month or year count. Be sure to adjust the month and year as you count backward.
  • Use Tools for Long Periods: For subtracting large numbers of days, or to ensure accuracy, consider using online calculators or date functions in spreadsheet programs.
  • Understand the Context: If you're calculating business days, remember to exclude weekends and possibly public holidays, depending on the context of your calculation.

How to Add Days to a Date

Adding days to a date is essential for planning future events, deadlines, or simply counting ahead. Similar to subtracting days, this process is straightforward and doesn't require considering leap years for most short-term calculations. Here’s a quick guide:

  1. Identify the Start Date: Choose the date you want to begin counting from. This is your reference point.
  2. Determine the Number of Days to Add: Decide how many days you want to add to your start date.
  3. Calculate the New Date: You can add the days manually using a calendar, use an online date calculator, or employ simple arithmetic to discover the future date.

This approach helps with projecting deadlines, anticipating future events, or calculating the date after a specified period.

Tips for Adding Days to a Date

  • Month and Year Transitions: Just as with subtracting days, when adding days causes you to cross into a new month or year, ensure to correctly adjust the month and year in your final date.
  • Leap Days: When adding a large number of days that span over February in a leap year, remember to account for the extra day in February (February 29).
  • Weekends and Holidays: If your calculation is for business or school days, remember to exclude weekends and public holidays from your count. This consideration is more critical when adding days, as you're planning into the future.