Add or subtract days, weeks, months and years from a date. Pick a month-end rule and see the result date, weekday and ISO week. Fast, free, and built for simple browser-based workflows.
Quick add
Calculated in this browser tab. The date you pick is not sent anywhere.
Need the number of days between two dates instead? Days Between Dates
Result date
Pick a start date, enter how many years/months/weeks/days, or try the example.
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Date Calculator is a free online tool that adds or subtracts years, months, weeks and days from any date. Enter a start date, choose Add or Subtract, type how many of each unit, and it shows the result date along with its weekday, day of the year and ISO week number.
It earns its keep when you need a date a known span away: a 90-day return deadline, the date six weeks before an event, when a two-year warranty expires, or a reminder date 180 days before a renewal. The quick +7/+30/+90-day buttons cover the common spans in one click, and the year, month, week and day fields handle an exact span when you already know it, including moving backward with Subtract.
Everything is calculated inside your browser, and the date you enter is never sent to a server or stored anywhere. That makes it safe to use for a client's contract deadline, a confidential project date, or any other date you would rather not type into a site you do not control. Dates centuries in the past or future are calculated with the same whole-day precision as next week.
Enter a date in Start from this date, or click Today to use today's date.
Pick Add to move forward from the start date, or Subtract to move backward.
Type a number into Years, Months, Weeks and Days, or click a quick-add button like +30 days to fill Days for you.
The result date appears as the headline, with its ISO date, weekday, day of the year, ISO week and days from today below it - each row has its own copy button.
Yes! All our tools are 100% free to use with no hidden costs, no registration required, and no credit card needed.
Absolutely. All tools run entirely in your browser (client-side). Your data never leaves your device and is not sent to our servers.
Yes, once the page is loaded, the tool will continue to work even if you lose internet connection since it runs in your browser.
Yes! All our tools are free for both personal and commercial use.
Pick a start date, choose Add or Subtract, then type a number into Days (or Years, Months and Weeks for a longer span) and the result appears immediately. The quick-add buttons below the fields fill in a common span, such as +30 or +90 days, in one click.
It depends on the month-end rule in More options. The default clamps to that month's last day, so January 31 plus one month becomes February 28, or 29 in a leap year. Switching to "Roll over into the next month" carries the extra days forward instead, landing on March 2 or 3.
Yes. Choose Subtract and the same Years, Months, Weeks and Days fields move the date backward instead of forward. A negative number has the same effect as switching modes: entering -5 under Add gives the same result as 5 under Subtract.
Years and months are applied first, as a single number of months using the month-end rule you chose, and weeks and days are added afterward. The rule note under the result states this each time, since the order can change the answer when a month-end is involved.
Yes, for any date from the year 1 to the year 9999. If a calculation would land outside that range - for example, adding a million days - it shows a message instead of an incorrect date.
No. Years, Months, Weeks and Days all take whole numbers only; a value like 1.5 is flagged and nothing is calculated until it is corrected. Leave a field at 0 if you don't need it.
Day of the year is the result date's position in its calendar year, such as 276 of 365. ISO week is its week number under the ISO 8601 standard, where week 1 contains the year's first Thursday, shown in the form 2027-W01.
No. Dates are calculated as calendar dates, not moments in time, so the result date is the same everywhere. Only the Today button, which reads the current date from your device's clock, depends on your local time zone.
There is no fixed limit on the numbers themselves, but the result date must stay within the year 1 to year 9999 range. An amount that would land outside it shows a clear message instead of a wrong date, so you can try a smaller number.