Date Calculator: Add or Subtract Days from a Date
Find the date that is a number of days, weeks, months or years before or after any date, such as 90 days from today or 6 months from a start date. You can also count working days only, skipping weekends. The result shows the day of the week and how far it is from today.
Common dates from your start date
| Period | Date after | Date before |
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How to use the date calculator
- Choose the start date. It is set to today; click Use today to go back to it.
- Choose Add to find a later date or Subtract to find an earlier date.
- Enter the years, months, weeks and days, or tap a quick button such as 90 days. You can fill in more than one box, for example 1 year and 15 days.
- To skip weekends, choose Working days. Use Mon–Fri for a five-day week, or Mon–Sat if Saturday is a working day for you.
The answer updates as you type. The table below the result lists the most-searched periods, such as 30, 60, 90 and 180 days, before and after your start date.
How the date is calculated
The calculator uses the Gregorian calendar, which is the calendar used for official dates in India and most countries. Leap years are included: a year is a leap year if it can be divided by 4, except century years, which must be divisible by 400. So 2028 is a leap year, while 2100 is not.
- Days and weeks are counted exactly. One week is always 7 days.
- Months and years move the calendar month, not a fixed number of days. 15 March plus 1 month is 15 April.
- Month ends: if the new month is shorter, the result is the last day of that month. For example, 31 January 2027 plus 1 month is 28 February 2027, and 29 February 2028 plus 1 year is 28 February 2029.
- Order: years and months are added first, then weeks and days.
- Working days: the count starts from the next day and skips Saturdays and Sundays (or only Sundays). Public holidays are not skipped, because they differ by state, company and bank.
Some rules count the start date as day 1, which makes the result one day earlier. If you need to include the start date, subtract one day from the number you enter.
When do you need a date calculator?
- Deadlines and notice periods: the last date of a 30-, 60- or 90-day notice period, or a reply due within 15 days.
- Payments and bills: a due date 45 days after an invoice date, or the date an EMI or subscription renews.
- Health and personal: a follow-up visit after 6 weeks, or a reminder 180 days later.
- Travel and documents: checking whether a stay or validity period ends before a given date.
- Projects: finding a delivery date that is 20 working days away.
Laws, contracts and banks can each have their own rules for counting days, such as whether the first day or a holiday counts. For legal or official deadlines, check the wording of the document or ask a professional, and use this tool to check your arithmetic.
To find the number of days between two dates instead, use the Time Duration Calculator. To work out exact age from a date of birth, use the Age Calculator.
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Frequently asked questions
What date is 90 days from today?
Leave the start date as today, choose Add, and tap 90 days. The result shows the date and day of the week. The table also lists 30, 60 and 180 days from today.
Is the start date included in the count?
No. Day 1 is the day after the start date, which is how most date calculators and calendars count. If your rule counts the start date as day 1, enter one day less.
How do you add months to a date like 31 January?
The month changes and the day stays the same. If that day does not exist in the new month, the last day of the month is used, so 31 January + 1 month is 28 February, or 29 February in a leap year.
Can I skip weekends and holidays?
You can skip weekends by choosing Working days (Mon–Fri) or (Mon–Sat). Public holidays are not skipped automatically, because holiday lists are different for each state and organisation. Add one day for each holiday in your period.
How do I find a date in the past?
Choose Subtract. For example, to find the date 45 days before a due date, enter the due date as the start date, choose Subtract and enter 45 days.
Does it handle leap years?
Yes. The calculator uses the Gregorian calendar rules, so 29 February is included in leap years such as 2028 and skipped in other years.
Is my data saved?
No. The calculation runs in your browser and the dates you enter are not sent to our server.
About this tool. The results use standard Gregorian calendar arithmetic in your browser. Before publishing, we checked them against hand-worked examples, including month ends, leap years (29 February), crossing a year end and working-day counts over weekends. Public holidays are not included.
Last reviewed: October 2026.