Date Calculator to Add or Subtract Days, Months and Years

Recruitment paperwork is full of relative dates. A notification says applications close 21 days after publication. A caste certificate must have been issued within a stated number of months before the closing date. An age clause says not more than 27 years as on 1 August, which quietly fixes the earliest qualifying date of birth. Each needs a date added to or subtracted from another.

This calculator does that arithmetic the way an office clerk does it on a wall calendar. Pick a starting date, choose Add or Subtract, and fill in any mix of days, weeks, months and years. The result shows the new date, its weekday and the number of days and weeks between the two, with a working panel so you can see what was applied.

The age calculator on this site tells you how old you are on a date. This one tells you which date lies a given distance from another.

1. Set the starting date, which defaults to today, to the date printed in the notification or on the document.
2. Choose Add to move forward in time or Subtract to move backward.
3. Enter the offset in any combination of days, weeks, months and years.
4. Read the resulting date and its weekday in the result panel.
5. Check the working panel to confirm the offset that was applied.

Years and months are applied first. The tool moves to the same day of the month in the target month, and if that day does not exist there, it uses the last day of that month. Weeks and days are then added as a plain count of calendar days. Under Subtract, every part of the offset is reversed.

The starting date itself is never counted, so 1 August plus 21 days is 22 August. Days apart is the calendar difference between the start and the result, so leap days inside the span are included.

• Order of application: years, then months, then weeks and days
• Month-end rule: 31 January plus 1 month is 28 February in a common year, since February has no 31st
• Days apart: whole calendar days between the two dates, shown as a positive number in either direction
• Weeks apart: days apart divided by 7, to one decimal place
• Input limits: up to 20,000 days, 2,000 weeks, 600 months and 200 years
• The result stays empty until at least one offset field is above zero

Hypothetical: a notification fixes the age band as 18 to 27 years as on 01/08/2026. Enter 01/08/2026, choose Subtract and type 27 in the years field. The tool returns 1 August 1999, a Sunday, 9,862 days apart (27 years including seven leap days). Repeat with 18 years to get 1 August 2008, a Friday. SSC notifications have printed such a band as born not earlier than the day after the upper anniversary and not later than the lower anniversary itself, so read the wording before deciding which side of 1 August 1999 you fall on.

Hypothetical: a certificate dated 31/01/2026 must be renewed within 1 month and 21 days. With Add selected, the tool first moves one month ahead and clamps to 28 February 2026, then adds 21 days to reach 21 March 2026, a Saturday, 49 days from the start. A plain count of 52 days would have given 24 March.

The headline date is the answer. The weekday beside it is the quickest sanity check, since a closing date that lands on a Sunday hints that the board meant the next working day, or that you typed the wrong month.

Days apart is the straight calendar distance and is the number to use when a rule is written in days. Weeks apart is the same figure divided by seven, there only to give a feel for the span.

• Counting the starting date. A window that opens on 10 March and runs for 21 days closes on 31 March.
• Expecting 30 days per month. One month from 31 January is 28 February, and one month from 15 February is 15 March, 28 days later.
• Adding days before months in your head. The tool applies years and months first, so 31 January plus 1 month and 21 days is 21 March rather than 24 March.
• Using today's date instead of the notification's reference date for an age clause.
• Treating the result as a working day. The tool does not shift a result that falls on a weekend or holiday; the notification decides whether that matters.

All dates are handled as plain calendar dates without a time of day, so there is no time-zone shift and no off-by-one from midnight. Leap years follow the standard Gregorian rule.

The tool does not know your notification. It cannot tell you whether a board counts the publication day, whether a deadline on a holiday rolls forward, or how an age clause is phrased. The notification text settles those.

Dates are shown in the long Indian format with the weekday. When copying a result onto a form, convert it to the DD/MM/YYYY style the form asks for.