How do I calculate the number of days between two dates?

Use the Date Difference mode, enter the start date and end date, and the page will return the total days plus a calendar-style years, months, and days breakdown.

Can I find what date is 90 days from today?

Yes. Switch to Add / Subtract Date, use today or any other base date, then add 90 days. The result will show the resulting date and weekday.

What does include end date mean?

It means the final date is counted as part of the span instead of being treated as the stopping boundary. This is useful for planning, booking, and scheduling tasks.

Can I add or subtract dates on this page too?

Yes. Switch to Add / Subtract Date, enter a base date, choose add or subtract, and then supply the years, months, weeks, and days you want to move.

Why is calendar difference not the same as total days?

Total days is a single full count. A years-months-days breakdown follows the calendar, so month length and date boundaries affect how the same span is expressed.

When should I use a business days calculator instead?

Use a business days calculator when weekends, workdays, or holiday exclusions affect the answer. This page is for general calendar math rather than weekday-aware scheduling.

Date Calculator

To calculate the difference between two dates or add and subtract dates and time from a base date, enter the dates below. The calculator returns the calendar difference in years, months, and days, plus the total days, weeks, and months between them — the broad entry point before workday or countdown-specific tasks.

Choose a date task

Switch between measuring the difference between two dates and calculating a future or past date from one base date.

Start date

Use the earlier date when possible to keep the difference result straightforward.

End date

Use today for a current date comparison, or pick any future date to measure ahead.

Include the end date in the count

The calculation runs in your browser. If you copy the link, the current dates and mode are included in the URL.

Results update instantly as inputs change, which makes it easy to compare dates without reloading.

Date result

Review the calendar difference or the resulting shifted date below.

Choose a mode and enter dates

The page will show a ready result as soon as the required dates for the selected mode are valid.

How this date calculator works

This page handles the two most common general date queries: days between dates and what date you get after adding or subtracting time. Date Difference compares one calendar date with another, while Add / Subtract Date moves a base date by years, months, weeks, and days.

1. Choose the task you want to solve

Use Date Difference for two-date comparisons, or Add / Subtract Date when you already know the base date and the amount of time to move.

2. Enter the required dates and options

For differences, supply a start date and an end date. For shifts, supply one base date and the amount of time to add or subtract.

3. Read the calendar-based result

The result shows either the full date difference or the new target date, along with supporting metrics that help explain the outcome.

Why this page focuses on general date math

Date tools cover many different intents, but the broadest search patterns are usually days between dates, date difference, and what date comes after adding or subtracting time.

Queries like "how many days between two dates" or "what date is 90 days from today" fit this page naturally because they are general calendar-math tasks.

This page does not try to solve business days, holiday rules, or event countdowns. Those are better handled by dedicated pages with their own logic and search intent.

Calendar math is not the same as a raw day count. Month lengths vary, and year boundaries change the breakdown when you express a result in years, months, and days.

Including the end date changes the total count for some workflows, so this page lets users make that choice explicitly.

Sources and references

These public references support the page's date-difference framing, add-or-subtract behavior, and leap-year-aware calendar logic.

timeanddate.com: Date Duration Calculator

Public reference for counting days between two dates, including the optional include-end-date behavior.

timeanddate.com: Date Calculator Help

Public reference for adding or subtracting years, months, weeks, and days from a starting date.

NIST: Leap Seconds FAQs

Public explanation of leap-year rules that helps support calendar-aware handling of month and year boundaries.

Date calculator FAQ

How do I calculate the number of days between two dates?: Use the Date Difference mode, enter the start date and end date, and the page will return the total days plus a calendar-style years, months, and days breakdown.
Can I find what date is 90 days from today?: Yes. Switch to Add / Subtract Date, use today or any other base date, then add 90 days. The result will show the resulting date and weekday.
What does include end date mean?: It means the final date is counted as part of the span instead of being treated as the stopping boundary. This is useful for planning, booking, and scheduling tasks.
Can I add or subtract dates on this page too?: Yes. Switch to Add / Subtract Date, enter a base date, choose add or subtract, and then supply the years, months, weeks, and days you want to move.
Why is calendar difference not the same as total days?: Total days is a single full count. A years-months-days breakdown follows the calendar, so month length and date boundaries affect how the same span is expressed.
When should I use a business days calculator instead?: Use a business days calculator when weekends, workdays, or holiday exclusions affect the answer. This page is for general calendar math rather than weekday-aware scheduling.

Related date tools

This page is the broad entry point for date math. Use the focused date pages when the real task is workday rules or time remaining until a target date.

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Business Days Calculator

Move from general date math into weekday-aware counting, deadline planning, and add or subtract business days.

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Countdown Calculator

Move from general date math into a single target-date question: how much time is left until the event?

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Age Calculator

Switch to the age tools cluster when the calendar question is really about birthdays, current age, or age on a chosen date.

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