Days Calculator
Add or subtract days from any date and get the resulting date and weekday.
How to use the Days Calculator
- Pick a start date.
- Enter the number of days and choose add or subtract.
- Read the result date and its day of the week.
Result = start date ± number of days
About the Days Calculator
This calculator adds or subtracts a number of days from any starting date and tells you the exact date you land on, using result = start date +/- days. Beyond the resulting date it also shows the day of the week that date falls on, and how many days it is from today, so you can see at a glance whether a deadline lands on a weekend or how far off it is.
It is built for the common everyday question of counting forward or backward from a fixed point: a 30-day return window, a 90-day notice period, a 45-day payment term, or a milestone a set number of days out. Pick the start date, enter the day count, and choose add or subtract to get an answer that correctly accounts for month lengths and leap years.
Note that this is different from measuring the gap between two known dates. If you already have both dates and want the number of days between them, use the Date Difference Calculator instead. To shift a date by whole months rather than days, try the Month Calculator.
Frequently asked questions
What does this calculator do?
It takes a start date and adds or subtracts a number of days, then shows the resulting date, the weekday it falls on, and how many days away it is from today. It is ideal for deadlines and notice periods.
How is it different from a date difference calculator?
This tool shifts one date by a number of days to find a new date. A date difference calculator does the opposite: you give it two dates and it counts the days between them. Use this when you know the span but not the end date.
Does it handle leap years and different month lengths?
Yes. The calculation uses real calendar dates, so it correctly accounts for 28, 29, 30 and 31-day months and for leap years. You do not need to adjust anything for February or year boundaries.
Can I count backward from a date?
Yes. Choose the subtract option and the tool counts backward by the number of days you enter, returning the earlier date. This is useful for working out when something needed to start to meet a given deadline.
Does it show the day of the week?
Yes. Along with the result date it reports which weekday that date is, so you can immediately tell if a deadline or milestone falls on a weekend or a working day.