What is a date calculator?
A date calculator does two jobs. It counts the number of days between two dates, and it finds the date that falls a set number of days, weeks, months or years before or after a start date. This online date calculator gives you the difference in days, in years, months and days, in weeks, in hours and minutes, and as business days that skip weekends. It is free and works on any phone or computer.
Typical uses: counting days until an exam or wedding, working out a notice period or visa stay, finding the IRCTC advance booking date, planning project deadlines in working days, checking a warranty or return window, and answering "what date is 90 days from today?"
How to use the date calculator
Count days between two dates
- Choose Count days between two dates.
- Enter the start and end dates. The start date defaults to today, so this doubles as a date calculator from today.
- Choose whether to count the end date. The standard difference excludes the start day; choose "include both" when you count days of a trip or leave where both the first and last day matter.
Add or subtract days from a date
- Choose Add to a date or Subtract from a date.
- Enter any mix of years, months, weeks and days, for example 0 years, 6 months, 0 weeks and 15 days.
- Pick calendar days, or business days if you need a deadline that skips Saturdays and Sundays.
Date calculator between two dates: the formula
Computers store each date as a day number. The difference between two dates is simply:
Days = Day number (end date) − Day number (start date)
- Weeks = days ÷ 7, with the remainder shown as extra days.
- Hours = days × 24 and minutes = days × 1,440.
- Years, months and days are found by subtracting year, month and day separately and borrowing a month (using the real length of the previous month) when the days go negative.
- Business days = number of Mondays to Fridays in the range, counted as 5 per full week plus the weekdays in the leftover days.
Worked example
From 18 September 2026 to 31 December 2026 there are 104 days. That is 3 months and 13 days, or 14 weeks and 6 days. Of those 104 days, 74 are business days (Monday to Friday) and 30 are weekend days. If you include both the start and end date, the count becomes 105 days.
For the other mode: 18 September 2026 plus 90 days is 17 December 2026, a Thursday. The same start date plus 90 business days lands on 22 January 2027, because weekends are skipped.
Date calculator in years, months and days
Months are not all the same length, so "how many months between two dates" has no single-number answer in days. This date calculator in years, months and days uses calendar months: from 15 January to 15 March is exactly 2 months, even though that is 59 days (60 in a leap year). When you add months, the day of the month is kept; if the target month is shorter, the result moves to its last day. So 31 January + 1 month gives 28 February (29 in a leap year), which matches how banks and most contracts treat month ends.
Adding and subtracting days: common questions
| Question | Enter | Answer (from 18 Sep 2026) |
|---|---|---|
| What date is 30 days from today? | Add 30 days | 18 October 2026 |
| What date is 90 days from today? | Add 90 days | 17 December 2026 |
| What date was 100 days ago? | Subtract 100 days | 10 June 2026 |
| 6 months from today? | Add 6 months | 18 March 2027 |
| 2 weeks before today? | Subtract 2 weeks | 4 September 2026 |
Date calculator for IRCTC railway ticket booking
Indian Railways opens reservations a fixed number of days before the journey date, excluding the journey day itself. The advance reservation period was cut from 120 days to 60 days from 1 November 2024. To use this as a date calculator for railway ticket booking, choose Subtract, enter 60 days and set your journey date as the start date: the result is the day booking opens. Always confirm the current rule on the IRCTC website before a holiday rush, because Railways changes it from time to time.
Business days and working days
Offices, courts and banks count deadlines in working days. Pick "business days" in add mode to find a due date such as "within 15 working days", or read the business-day count in the difference mode to know how many working days a project has. This calculator skips Saturdays and Sundays only; subtract public holidays like Diwali, Holi or Independence Day yourself because holiday lists differ by state and employer.
Other uses of a date calculator
- Age and birthdays – count days since you were born or until your next birthday. For exact age with a birthday countdown, use the age calculator.
- Pregnancy – add 280 days (40 weeks) to the first day of the last period to estimate a due date. The pregnancy due date calculator does this with trimester dates.
- Retirement – add years to a date of birth to see your date of retirement, e.g. DOB + 60 years. Many government rules retire you on the last day of that month; plan your savings with the retirement calculator.
- Visa and travel – count days of stay against a 90- or 180-day limit, including both the entry and exit date.
- Loans and bills – count days for interest calculations or late fees.
How to calculate dates in Excel
Excel stores dates as numbers, so subtraction works directly: =B2-A2 gives the days between two dates. Use =NETWORKDAYS(A2,B2) for working days (it counts both ends), =A2+90 to add days, =EDATE(A2,6) to add months and =WORKDAY(A2,15) for a date 15 business days later. =DATEDIF(A2,B2,"M") returns whole months between dates.
By hand, count the days left in the start month, add the full months in between using their real lengths (31, 28/29, 31, 30 …), then add the days of the end month. It works, but it is slow and easy to get wrong – which is why a date calculator is handy.
Date calculator: how many days, weeks and years
Use the date calculator online to answer the three most common questions at once. Pick "Count days between two dates" and the result shows how many days, how many weeks and how many years sit between the dates, plus a months and days breakdown.
Date calculator: number of days between two dates
The number of days is simply the end date minus the start date. From 15 June 2026 to 31 December 2026 the date calculator difference is 199 days, which is 28 weeks and 3 days. If you need the end date counted too, add one day (200).
Date calculator in months and days, or in days only
For the same dates, the date calculator in months and days shows 6 months and 16 days, while the date calculator in days shows 199. Months have uneven lengths, so always quote days when accuracy matters, such as for notice periods or interest.
Date calculator: how many years old is a date?
For someone born on 10 May 1990, 19 September 2026 is 13,281 days later, or 36 years, 4 months and 9 days. For a birthday-focused view, the age calculator adds the next birthday countdown.
Date calculator with time and hours
This page counts whole calendar days. If you need a date calculator with time, for example from 9:00 AM on Monday to 5:30 PM on Wednesday, count the full days first (2 days) and then add the time difference (8 hours 30 minutes) using the time calculator. A date calculator with hours works the same way: 2 days and 8.5 hours equals 56.5 hours.
Date calculator and time zones
A time zone calculator matters only when the start and end are in different places. Convert both moments to the same zone first: India is UTC+5:30 all year, so 11 PM in London in winter is already 4:30 AM the next day in India, which can change the day count by one.
Date calculator: add days or subtract days
To add days, choose "Add to a date" in the date calculator, enter the start date and the number of days; to subtract days, pick "Subtract from a date" instead. For example, 15 June 2026 plus 90 days is Sunday, 13 September 2026.
Calculate date x days from today
Leave the start date as today and enter the number of days. Counting from 19 September 2026, 60 days from today is Wednesday, 18 November 2026. This date calculator with number of days also works backwards when you subtract.
Date calculator for IRCTC ticket booking
Indian Railways opens reserved tickets 60 days in advance, not counting the journey date. To find when booking opens, subtract 60 days from your travel date in the date calculator for IRCTC ticket booking, and check the current rule on the IRCTC site before planning.
Date calculator for pregnancy and period dates
As a date calculator for pregnancy, add 280 days (40 weeks) to the first day of the last menstrual period to estimate the due date. The same add-days method gives a rough date calculator period estimate: add your usual cycle length (for example 28 days) to the start of your last period. For a full week-by-week view use the pregnancy calculator.
Date calculator for retirement
A date calculator for retirement adds your retirement age in years to your date of birth. Born 10 May 1970 with retirement at 60, you reach 60 on 10 May 2030; many Indian government rules then retire you on the last day of that month, 31 May 2030.
Date calculator quarterly, monthly and yearly
Quarterly, monthly and yearly schedules all work the same way in the date calculator: add 3 months at a time for quarters (from 1 April 2026 they start on 1 July, 1 October and 1 January), 1 month for a monthly plan and 12 months for a yearly one. The Indian financial year from 1 April 2026 to 31 March 2027 covers 364 days between the dates, or 365 counting both ends.
Date calculator: June 2026 and July 2026 examples
June 2026 starts on Monday 1 June and ends on Tuesday 30 June, so a date calculator for June 2026 shows 22 weekdays in the month. Adding 30 days to 1 June 2026 lands on 1 July 2026, a Wednesday, which is a handy check for any date calculator July 2026 deadline.
Date calculator India: legal and official deadlines
In India, a date calculator for legal limitation periods usually excludes the day the event happened (Section 12 of the Limitation Act, 1963) and starts counting from the next day. Courts in Australia follow a similar rule: in QLD and Victoria the date calculator logic under the interpretation acts excludes the first day, and a deadline falling on a weekend or holiday moves to the next business day.
Date calculator in Hindi, Tamil, Kannada, Urdu and other languages
Dates are numbers, so the date calculator gives the same answer for a calendar printed in Hindi, Tamil, Kannada, Gujarati or Urdu as long as you enter the Gregorian (English) date. For Vikram Samvat or Nepali dates, convert the Nepali to English date first, then count days here.
Date calculator.xlsx: doing the same in a spreadsheet
If you want a date calculator.xlsx file, the Excel formulas above are all you need: put the start date in A2, the end date in B2 and use =B2-A2. There is no need for a date calculator free download, because this page works offline once loaded, on phone or desktop.
Frequently asked questions
How do I count the days between two dates?
Choose "Count days between two dates", enter the start and end date, and read the total. The calculator also shows the gap in years, months and days, weeks, and business days.
Does the date calculator include the end date?
By default it gives the standard difference, which counts the end date but not the start date. Select "include both" to add one day, for example when counting leave or trip days.
What date is 90 days from today?
From 18 September 2026, 90 days later is 17 December 2026. Choose "Add to a date", keep today as the start date and enter 90 days to check from any date.
How many business days are between two dates?
The calculator counts Monday to Friday between the dates and shows them as business days. Public holidays are not removed, so subtract them yourself.
How do I subtract days from a date?
Choose "Subtract from a date", enter the start date and the number of days, weeks, months or years to go back. The result date and weekday appear instantly.
How many weeks are between two dates?
Divide the total days by 7. The calculator shows it for you as whole weeks plus leftover days.
What happens when I add a month to 31 January?
The result is the last day of February (28 or 29), because February has no 31st. This matches how most banks and contracts handle month ends.
How do I calculate a date x days from today?
Leave the start date as today, choose "Add to a date" and type the number of days. For example, 60 days from 19 September 2026 is 18 November 2026.
Can the date calculator include time?
It counts whole days. For a date and time gap, count the days here and add the hours and minutes with the time calculator, or multiply days by 24 to get hours.
What is the date calculator formula?
Days between two dates = end date minus start date. To add days, move forward that many calendar days; to add months, keep the day number and clamp to the month end if needed.
Last updated 2026-09-18