Add or Subtract Days – Date Calculator
Find out what date it will be a number of days, weeks, months, or years from any date — or before it. Optionally count business days only. Free, no sign-up, and everything runs in your browser — nothing is stored or uploaded.
This free date calculator lets you add or subtract days — or weeks, months, and years — from any date, and tells you the exact date and day of the week you land on. Need to know what date is 30 days from today, when a 90-day deadline falls, or which day a contract ends? Enter a start date, choose how much to add or subtract, and read the answer instantly. You can also count business days only, skipping weekends. It is built for anyone tracking deadlines, notice periods, due dates, or plans — freelancers, HR and legal teams, project managers, students, and anyone who would otherwise count on a calendar. Everything runs in your browser; nothing is stored or uploaded. Pick a date above to start.
What does this tool do?
It takes a starting date and shifts it forward or backward by an amount you choose, then shows the resulting date and weekday. You can:
- Add or subtract days, weeks, months, or years.
- Count business days only (Monday–Friday), skipping weekends.
- Jump to today with one click as your start date.
- See the day of the week for the result, not just the date.
Why use this tool?
Counting days on a calendar is slow and easy to get wrong — especially across month ends, leap years, or long stretches like 90 or 180 days. A single miscount can mean a missed deadline or a wrong due date. This calculator applies the exact date math for you, handles month lengths and leap years automatically, and gives the weekday too, which matters when weekends affect a deadline.
How the tool works
- Days, weeks, years shift the date by the exact number you enter (weeks are simply ×7 days).
- Months move by calendar month, so the day-of-month is kept where possible and month lengths are respected.
- Business days mode steps one day at a time and only counts Monday to Friday, skipping Saturdays and Sundays — so "10 business days" lands two calendar weeks later, not ten calendar days.
- Leap years and varying month lengths are handled automatically by the date engine.
Note: business-day mode counts weekends only. It does not know public holidays, which vary by country and region.
How to use the tool
- Choose a start date, or click Today.
- Pick Add or Subtract.
- Enter the amount and choose the unit (days, weeks, months, years).
- Optionally tick business days only for day-based counts.
- Read the result date and weekday instantly.
Practical examples
90 days from today
Set today as the start, add 90 days, and see the exact deadline date and weekday for a payment or return window.
Notice period
Add 30 days to a resignation date to find the last working day, or subtract to see when notice had to be given.
Business-day deadline
Add 10 business days to an invoice date to find a due date that skips weekends.
Anniversary or renewal
Add 1 year to a start date to find a renewal or anniversary that falls on the correct weekday.
Common use cases
- Legal & HR: notice periods, probation ends, contract and filing deadlines.
- Finance: payment terms like net-30 or net-90, return windows.
- Project management: milestone and delivery dates, including business-day counts.
- Students: submission deadlines and study schedules.
- Everyday planning: travel, appointments, and countdowns.
Tips & best practices
- Use business-day mode for work deadlines, but add extra time manually for public holidays.
- Check the weekday of the result — a deadline that falls on a weekend often moves to the next working day.
- For "months," remember the day-of-month is kept where the target month allows it.
- Use Subtract to work backward from a fixed deadline and find your latest start date.
Frequently Asked Questions
What date is 90 days from today?
Set today as the start date, choose Add, enter 90, and keep the unit on days. The tool shows the exact date and weekday 90 days ahead.
What is the difference between calendar days and business days?
Calendar days count every day. Business days count only Monday to Friday, skipping weekends — so 10 business days is longer on the calendar than 10 calendar days.
Does it account for leap years?
Yes. The underlying date engine handles leap years and different month lengths automatically, so results stay accurate across February and year boundaries.
Does it include public holidays?
No. Business-day mode skips weekends only. Public holidays differ by country and region, so add any holidays manually if they affect your deadline.
How does adding months work?
It moves by calendar month and keeps the same day-of-month where the target month has that day, respecting each month's length.
Can I subtract to go back in time?
Yes. Choose Subtract to move backward from your start date — useful for finding when a notice or deadline period began.
Does it show the day of the week?
Yes. The result includes the weekday, which matters when weekends or working days affect a deadline.
Is it free and private?
Completely free, with no account. All calculations run in your browser, so your dates are never uploaded or stored on a server.