Date Calculator
Use this free date calculator to find the exact number of days between dates — or add or subtract days, weeks, months and years from any date. Whether you need a days calculator for project planning, a day counter for a countdown, or a date to date calculator for contract terms, this tool gives you the answer in seconds — including business days and weekdays. All calculations run locally in your browser: your dates never leave your device.
Click a date to set the start, then click again to set the end. Supported range: 0001-01-01 to 9999-12-31.
Day 1 is the day after the start date; the end date counts (legal / contract / tax convention).
Days Between Two Dates
- Switch to the “Days Between Two Dates” tab
- Click the start date on the calendar, then click the end date
- Choose a counting rule (exclude start day is the default)
- The result updates instantly — total days, months, weeks, business days and weekdays
Add to or Subtract from a Date
- Switch to the “Add or Subtract” tab
- Pick the start date (or press Today), then choose Add or Subtract
- Enter amounts in years, months, weeks and days — combine freely
- See the result date in US, EU and ISO formats
Or use the quick presets below the calculator — tap +30 days or −90 days and the date is computed instantly.
Need the duration between two times? Try the time duration calculator. How old are you exactly? Try the age calculator to find your age in years, months and days.
How to Use This Free Day Calculator
Days between two dates: open the Days Between Two Dates tab, click the start date on the calendar, then click the end date. Choose a counting rule — by default the start day is excluded and the end day is included, the convention used for legal, contract and tax deadlines. The result shows total days, combined years/months/days, weeks, business days (weekends excluded) and the weekday of both dates.
Add or subtract from a date: open the Add or Subtract tab, pick a date (or press Today), choose Add or Subtract, and enter any combination of years, months, weeks and days. The result date appears in US, EU and ISO formats with the weekday.
Need a quick answer? Use the From Today presets below the calculator — tap +30 days or −90 days and the result is computed instantly. This days calculator is a pure day counter: no sign-up, no uploads — all calculations happen instantly in your browser, nothing is uploaded or stored.
Popular From Today Date Calculations
Need a date in the future? Use the preset buttons above the calculator — tap +30 days for 30 days from today, +60 days for 60 days from today, +90 days for 90 days from today, or +120 days and +180 days for 120 days from today and 180 days from today. You can also jump ahead 2 weeks from today, 3 months from today, or 6 months from today with a single tap.
Need a past date? The backward presets give you 30 days ago, 60 days ago, 90 days ago, 180 days ago, and 6 months ago from today instantly. Any of these can also be typed manually in the Add or Subtract tab — add or subtract any number of days, weeks, months or years from any date.
How to Calculate Days Between Two Dates Manually
You can count days between two dates by hand with four steps. Let's find the days from March 15 to June 1, 2026:
- Count whole years — none here (same year).
- Count whole months — March 15 to May 15 is 2 full months.
- Count the remaining days — May 15 to June 1 is 17 days (16 days left in May + 1 day in June).
- Convert and add — 2 months 17 days ≈ 78 days (16 + 30 + 31 + 1, counting from the day after March 15 through June 1).
This method — whole years, then whole months, then remaining days — is exactly how the calculator's combined result works, so your hand calculation and the tool will agree.
Leap Year Rules (Gregorian Calendar)
A year is a leap year if divisible by 4 — except century years, which must also be divisible by 400.
| Year | ÷ 4 | ÷ 100 | ÷ 400 | Leap? |
|---|---|---|---|---|
| 2024 | ✓ | ✗ | ✗ | ✅ |
| 2025 | ✗ | ✗ | ✗ | ❌ |
| 1900 | ✓ | ✓ | ✗ | ❌ |
| 2000 | ✓ | ✓ | ✓ | ✅ |
Date Calculation Edge Cases
How month-end, leap years and century years are handled — the same rules the calculator applies automatically.
| Calculation | Result |
|---|---|
| Jan 31, 2026 + 1 month | Feb 28, 2026 (month-end clamping) |
| Feb 28, 2024 + 1 day | Feb 29, 2024 (leap year) |
| Feb 28, 2025 + 1 day | Mar 1, 2025 (non-leap year) |
| Mar 15, 2026 − 30 days | Feb 13, 2026 (backward across months) |
| Jan 1, 2026 − 1 day | Dec 31, 2025 (across years) |
| Dec 31, 2024 + 1 day | Jan 1, 2025 (after a leap year) |
| Jan 1, 2028 + 1 year | Jan 1, 2029 (across a leap year) |
| Dec 31, 0099 + 1 day | Jan 1, 0100 (century boundary) |
| Feb 28, 2100 + 1 day | Mar 1, 2100 (century non-leap) |
| Feb 28, 2400 + 1 day | Feb 29, 2400 (century leap) |
How Many Days Are in Each Month?
Wondering how many days in February, how many days in June, how many days are in May, how many days are in August, or how many days are in November? Here's the full breakdown — the list below covers every month, with February at 28 days (29 in a leap year).
- How many days in January? 31 days.
- How many days are in February? 28 (29 in a leap year) days.
- How many days in March? 31 days.
- How many days are in April? 30 days.
- How many days in May? 31 days.
- How many days are in June? 30 days.
- How many days are in July? 31 days.
- How many days in August? 31 days.
- How many days in September? 30 days.
- How many days are in October? 31 days.
- How many days in November? 30 days.
- How many days are in December? 31 days.
| Month | Days |
|---|---|
| January | 31 |
| February | 28 (29 in a leap year) |
| March | 31 |
| April | 30 |
| May | 31 |
| June | 30 |
| July | 31 |
| August | 31 |
| September | 30 |
| October | 31 |
| November | 30 |
| December | 31 |
Need to count the actual days between two dates, or add days to a date? Use the date calculator above.
When to Use a Date Calculator
Project deadlines
Plan milestones and task due dates — a project deadline calculator for teams and freelancers.
Contract and lease terms
Check contract periods, expiry dates and renewal windows with a reliable contract date calculator.
Event planning
Count down to weddings, launches and meetings — an event countdown calculator for your big day.
Payroll and HR
Work out start dates, probation end dates and attendance periods with a payroll date calculator.
Legal deadlines
Track statutes of limitation, filing deadlines and notice periods — counting rules matter, and the counting rule is explicit here.
Personal planning
Birthdays, anniversaries, vacations and retirement — a days until calculator and days since calculator for what matters to you.
Date Calculator — FAQ
How to calculate the number of days between two dates?
Count from the day after the start date through the end date. Example: from January 31 to March 1, 2026 the result is 29 days, shown as 1 month 1 day — February has 28 days in 2026, so January 31 plus 1 month lands on February 28, then 1 more day reaches March 1.
How do I add days to a date?
Open the Add or Subtract tab, pick the start date, choose Add and enter the amount — days, weeks, months and years can be combined. Adding 90 days to January 1, 2026 gives April 1, 2026. Results show US, EU and ISO formats plus the weekday.
What is 30/60/90 days from today?
Tap the presets under the calculator: +30 days, +60 days or +90 days compute the date from today instantly; the backward presets give dates in the past. The result line shows exactly how many days from today the date is.
How many days are in each month?
January 31, February 28 (29 in a leap year), March 31, April 30, May 31, June 30, July 31, August 31, September 30, October 31, November 30, December 31. The full days-in-month table is on this page.
Does the calculator count the end date?
By default, no — the start day is excluded and the end day is included (Day 1 is the day after the start), the standard for legal, contract and tax deadlines. Switch the Counting Rule to Include both start and end days when both dates must count, e.g. custody days or hospital stays.
Is 2026 a leap year?
No — 2026 is not divisible by 4, so February has 28 days. A year is a leap year when divisible by 4, except century years (2100) which must also be divisible by 400 (2000, 2400).
Is the date calculator free and private?
Yes. This free day calculator runs entirely in your browser — local-only calculation, your dates never leave your device, nothing is uploaded or stored, and there is no sign-up.
What is the difference between calendar days and business days?
| Dimension | Calendar days | Business days |
|---|---|---|
| Counted | Every day, including weekends and holidays | Saturdays and Sundays excluded (public holidays are not excluded in this version) |
| Use for | Project spans, countdowns, personal planning | Contract terms, legal deadlines, approvals, notice periods |
| Example (Jan 1 – Mar 1, 2026) | 59 days | 41 days (default rule) |
How many days until a date? How many days since a date?
Use the Days Between Two Dates tab. For days until a date, set the start date to today and the end date to your target. For days since a past date, swap the dates and read the result as days since that day.
How many business days are between two dates?
The result panel shows Business days alongside calendar days. Business days exclude Saturdays and Sundays (public holidays are not excluded in this version). Example: January 1 to March 1, 2026 is 59 calendar days and 41 business days.
Disclaimer
Calendar days only — weekends are counted in the default result. The Business days result excludes weekends only; public holidays are not excluded in this version (see FAQ above). Based on the Gregorian calendar; dates before 1582 may not reflect historical calendars. For planning and estimation only — verify legal, contract, or financial deadlines with the relevant authority.
A manual calculation may introduce errors — use the calculator above for accurate results.
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