Date Calculator

The difference counts the start date and stops before the end date, like a countdown: Monday to the next Monday is 7 days. Tick Count the end date as well to include it, for example for a stay from 1 to 3 January (3 days). The same rule holds when the end date is before the start date: the count runs backwards from the start, the start date is counted and the end date only when the box is ticked, so 15 to 14 September with the box ticked is 2 days. Working days are Monday to Friday; tick Working days also leave out Singapore's public holidays to leave those out as well (the next answer says which).

Singapore's, as the Ministry of Manpower lists them for 2018 to 2027 (its yearly calendars, read on 14 October 2026), Polling Days included. A holiday on a Saturday leaves out no working day; one on a Sunday leaves out the next day that is not itself a public holiday, as section 4(2) of the Holidays Act 1998 says: Monday 1 June 2026 for Vesak Day, or Tuesday 24 January 2023, because that Monday was Chinese New Year. Every day left out is named in the result, both for a count between two dates and for working days added or subtracted. Outside 2018 to 2027 no list is known here, and the result says so when a count reaches those years; other countries' public holidays are not known to the tool.

The way an age is stated: whole years first, then whole months, then the remaining days, from the earlier date to the later one, on the dates as entered: 29 February 2024 and 28 February 2025 are 0 years, 11 months, 30 days whichever is the start date, and 31 January and 28 February 2026 are 0 months, 28 days either way round. With Count the end date as well ticked, the later date counts as a whole day, so the breakdown runs to the day after it: 1 to 3 January included is 3 days, and 29 February 2024 to 28 February 2025 included is 1 year, 0 months, 1 day. Adding a month to 31 January gives the last day of February, because 31 February does not exist; the result says so when that happens. Adding a duration applies years and months first, then weeks and days, then working days.

The Gregorian calendar, extended backwards (proleptic) for dates before 1582, with whole dates only and no clock times, so daylight-saving changes and time zones cannot alter a count. The Unix time shown in the facts is for midnight UTC of that date. The local clock fills in today's date. If the device time zone is Asia/Singapore, excluding Singapore public holidays starts selected; other time zones start with weekends only. You can change the checkbox, and an explicit shared-link setting takes precedence. The same dates and choices always give the same count.

The ISO 8601 week number: weeks start on Monday and week 1 is the week containing the year's first Thursday. Because of that, 1 January can belong to week 52 or 53 of the previous ISO year, and 31 December to week 1 of the next.

Once the page has loaded, yes. Nothing is fetched while you calculate.

No. The page loads a small script into your browser and every calculation runs on your device. You can check this yourself in the browser's network panel: after the page has loaded there are no upload requests. Closing the tab discards what you entered.

No. These basic tools are free and store nothing on our servers. The only limits are the tool's own: amounts are whole numbers up to 1,000,000 each (years, months, weeks, days and working days); dates, entered or calculated, run from the year 1 to the year 275,760 (a browser's date field takes them up to 13 September 275,760).

Nothing you open or type. While the tab is open, the tool pages keep a short list of the steps taken in it, in the tab's session storage: the step (page opened, started, succeeded, first success, used again or failed), the tool's name, the time, how many files were used and, for a failure, an error code; never a file name, the contents of a file or your text. It holds at most the latest 200 steps, and the browser deletes it when the tab closes. The page never sends it. Where a Report a problem button is shown, you can attach the last 20 steps to your report; nothing is attached unless you tick that box. In local storage the page keeps only choices you made: a Light or Dark theme until you choose System again, the language you picked with the EN / 中文 switch if it differs from your browser's language, and this tool in your recently used list if you switched that list on at the tools page.