Date Calculator

Count the days between two dates, or add and subtract days, weeks, months, and years from any date. Business days are counted for you.

Quick range

Enter a valid date in both fields to see the result.

Get Your Dates Right the First Time

Deadlines, notice periods, and delivery windows all turn on an exact day count. Measure the gap between two dates, or move a date forward and back by days, weeks, months, and years. Weekends are separated out for you.

Calendar days · Business days · Leap years

Why Use This Date Calculator?

Two Calculations in One

Measure a period between two dates, or shift a date forward and back. Switching tabs keeps everything you have already typed.

Working Days Counted

Every result splits business days from weekend days, so you can plan around a five-day week without counting squares on a calendar.

Month Ends Handled Properly

Adding a month to 31 January lands on 28 February, not 3 March. Leap years come straight from the calendar, so 2028 picks up its extra day.

Nothing Leaves Your Browser

Dates are processed locally with JavaScript. Contract dates, medical timelines, and private deadlines stay on your device.

How this Date Calculator works

Every date you enter is read as a plain calendar day and pinned to UTC midnight before any arithmetic runs. That single decision removes the most common bug in date tools: a range that crosses a daylight saving change coming back a day short. A March to November span measures the same in Berlin, Phoenix, and Sydney.

In days-between mode the tool subtracts the two timestamps and divides by the length of a day. The start day counts and the end day does not, because that is how notice periods, warranties, and payment terms are normally written. The checkbox flips that when you are measuring something inclusive, such as the length of a trip. Business days are counted by taking the whole weeks in the range, multiplying by five, then walking the leftover days one at a time and skipping every Saturday and Sunday. Public holidays are deliberately left in, since they differ by country and employer.

Adding and subtracting works differently. Years and months move the month number first and then clamp the day, so 31 January plus one month lands on 28 February instead of spilling into March. Weeks and days are applied afterwards as a straight day offset. The business-day option steps forward or backward one day at a time and only counts a step that lands on a weekday.

Leap years need no special handling. February 2028 gets its 29th day from the calendar itself, so any range crossing it picks up the extra day automatically.

How to use this Date Calculator

1

Pick a mode

Use "Days between dates" to measure a period, or "Add or subtract" to find a future or past date.

2

Enter your dates

Choose dates from the picker or type them in. The 7, 30, 90, and 365 day shortcuts are quicker still.

3

Read the result

Totals update as you type. Copy the summary with one click to drop it into an email or a spreadsheet.

Example Usage

Counting a project window and its working days:

Input
Start: 2026-03-01 · End: 2026-06-15 · Count the end day: off
Output
106 days · 15 weeks and 1 day · 3 months and 14 days · 75 business days

Frequently Asked Questions

How many days are there between two dates?
Pick a start date and an end date, and the tool counts every calendar day in between. By default the start day counts and the end day does not, which is how contracts and notice periods are usually read. Tick "Count the end day too" when you need both endpoints included, such as counting the length of a holiday.
Why does the result change when I tick "Count the end day too"?
It adds exactly one day. From 1 March to 8 March there are 7 days between the dates, but the trip itself covers 8 days if you count both the day you leave and the day you come back. Choose the option that matches what you are measuring.
How does the tool count business days?
It counts Monday to Friday and skips every Saturday and Sunday in the range. Public holidays are not removed because they differ by country, state, and company. If your deadline depends on holidays, subtract them yourself from the business day total.
Can I work out a date 90 days from today?
Yes. Switch to "Add or subtract", leave the start date as today, type 90 in the days field, and keep the operation on Add. The tool shows the full date with the day of the week, so you can see straight away if it lands on a weekend.
What happens when I add a month to 31 January?
The result is 28 February, or 29 February in a leap year. When the target month is shorter, the tool moves the date back to the last valid day instead of spilling into the next month. This matches how most contracts and billing cycles treat monthly periods.
Does the calculator handle leap years?
Yes. February 2028 and February 2032 are treated as 29-day months, so any range that crosses them picks up the extra day automatically. You do not need to adjust anything.
Why is the years, months, and days breakdown different from the total day count?
Months are not all the same length, so a calendar breakdown and a raw day count answer different questions. "3 months and 2 days" is easier to say out loud, while the total day count is what you need for interest, penalties, or shipping estimates. Both are shown side by side.
Can I enter dates in the past or a long way into the future?
Yes. The tool accepts historical dates and dates decades ahead, and it works the same in both directions. If you put the later date in the first box, it still reports a positive number of days and tells you the order was flipped.
Does the calculator use my time zone?
No, and that is deliberate. Every date is treated as plain calendar days, so a range that crosses a daylight saving change never gains or loses an hour and never reports an off-by-one day count.
Are my dates sent anywhere?
No. The whole calculation runs in your browser with JavaScript. Nothing is uploaded, stored, or logged, so you can use it for private deadlines, contract dates, and medical timelines.

Related Tools

Try It

Random Date Generator

Generate random dates with customizable ranges and formats. Perfect for testing and data generation.

Try It

Age Calculator

Calculate exact age in years, months, days.

Try It

Dates Sorter

Paste a list of dates and sort them in ascending or descending order instantly. Supports multiple date formats. Free, browser-based, no sign-up required.

Try It

Time Average Calculator

Calculate the average of multiple time values in hours, minutes, and seconds. Add unlimited entries, get real-time results, and copy the mean time instantly. Free and browser-based.

Try It

Auto Loan Calculator

Work out your monthly car payment, total interest, and payoff date.

Try It

Percentage Change Calculator

Find the percentage increase or decrease between two numbers, work back to the original value, and check percentage difference or percent error.

The Date Calculator is maintained by CodeItBro. We aim to provide the best free developer tools on the web. If you have feedback or suggestions, please visit our contact page.

Comments

Questions, corrections, and useful tips are welcome. Comments are reviewed before publication.

Loading comments...

Comments are stored and moderated using Cusdis Cloud. Email is optional. Privacy Policy

As featured on

CodeItBro - Free dev tools + practical guides to help you ship faster | Product HuntCodeItBro - Free Online Developer Tools badgeCodeItBro badge