Add Days to a Date (or Subtract Them)
What date is 90 days from today? Add or subtract days, weeks, months or years and get the exact date with its weekday.
Free forever, no sign-up and no limits, and this tool installs on its own so you can keep it on your home screen.
Pick a start date, say how far to jump (days, weeks, months or years, forwards or back) and get the exact date with its weekday. 90 days from today, 30 days before an invoice date, six months into a contract: all one glance.
How to use it
- Set the start dateIt defaults to today; change it for deadlines counted from some other day.
- Choose the jumpA number (the 30, 60, 90 and 180 chips fill it in one tap), a unit, and whether it lands after or before the start. Flip the Count toggle to step in working days instead.
- Read the dateThe result shows with its weekday, plus the true number of days in between.
The deadline arithmetic everyone does badly on fingers
"Within 90 days", "30 days notice", "valid for six months", obligations are written as offsets, but calendars are read as dates. Converting between the two by counting on a phone calendar is error-prone in exactly the ways that matter: February's length, a forgotten leap year, or the quiet difference between a month and 30 days.
This tool does the conversion exactly, and shows the day count it actually applied so a contract question (did they mean 90 days or three months?) surfaces immediately instead of at the deadline.
Days, months and the clamp rule
Days and weeks are exact: 90 days is 90 midnights, whatever the calendar does. Months and years move the calendar slot instead: 15 March plus one month is 15 April, even though that is 31 days. The awkward case is a start date near month end: 31 January plus one month clamps to the last day of February, because that is the only reading that never produces an impossible date. Standard date libraries, banks and courts all land on this behaviour; this tool matches them and says so.
Working days, when the contract says so
Some deadlines count every day and some count only working days, and the two drift apart fast: 90 calendar days is roughly 64 working days. The Count toggle switches the tool to working-day stepping, where each step skips Saturday and Sunday, so "10 working days from today" is answered in one tap rather than on fingers. Public holidays are not subtracted, deliberately: they differ by country, region and employer, and a silently applied wrong calendar is worse than an honest Monday-to-Friday count you can adjust yourself.
Counting back
The Before switch covers the other half of real use. Payment terms count back from delivery, cancellation windows count back from renewal, and visa rules count back from entry. The maths is symmetric but the mistakes are not, counting backwards over a year boundary by hand goes wrong more often, which is a good reason to let the calendar arithmetic do it.
Questions people ask
What date is 90 days from today?
The tool answers with today preloaded: type 90 and read the result. Ninety days is the classic contract and probation length, and it is not three months: depending on which months it crosses, three calendar months is 89 to 92 days. Deadlines care about which definition applies, which is why both units are offered.
Does adding days skip weekends?
Calendar days do not, and that is what most deadlines, visas and return windows mean. Flip the Count toggle to working days and every step skips Saturday and Sunday: 5 working days after a Friday is the next Friday. Public holidays are not skipped, they vary by country and employer, so allow for your own.
Why the 30, 60, 90 and 180 day presets?
Because deadlines cluster on them: 30-day returns and invoices, 60 and 90 day payment terms and probation periods, 180-day visa windows. One tap fills the number, and the unit switches to days so the chip means exactly what it says.
What happens with 31 January plus one month?
There is no 31 February, so the result clamps to the month's end: 28 February, or 29 in a leap year. This matches how the standard date libraries behave and how people read contracts. Adding 30 days instead lands on 1 or 2 March, different question, different answer, and the tool lets you ask either.
Do leap years throw the maths off?
They are handled exactly. Adding 365 days to a date is not the same as adding one year when 29 February falls in between, one year from 1 June 2023 is 1 June 2024, which is 366 days. Choosing the unit chooses the meaning.
Can I count backwards?
Yes, flip After to Before. Backwards is the invoicing direction: a payment due 14 days before delivery, a cancellation window 30 days before renewal, a booking that opens 6 months ahead.
Why does the result show the weekday?
Because deadlines that land on a Saturday move in practice. Seeing 'Sunday' next to the date is the earliest possible warning that the real deadline is a day or two different.