Add or Subtract Days
Shift a date by N days.
Shift a date by N days.
How to use Add or Subtract Days
- Pick a start date and choose add or subtract mode
- Enter a number of days, weeks, months, or years
- Read the resulting date and its day of the week
- Switch modes to count days between two dates instead
About Add or Subtract Days
Start with any date, choose Add or Subtract, and enter a whole number of days, weeks, months, or years to land on the exact resulting date, along with the weekday it falls on. This is the fast way to answer what date is a set number of days from a given date, whether you're counting forward to a deadline or backward to a start point. Adding months respects the calendar: January 31 plus one month clamps to the last day of February instead of overshooting into March.
Flip to the second mode to count the exact number of days between two dates. It returns the total days, the total weeks, a clean weeks-and-days split, and a full years, months, and days breakdown, and it still works if you enter the later date first. Because both modes treat dates as whole calendar days at local midnight, there is no timezone drift and every count stays accurate. You can lean on the add mode as a plain due-date calculator too: add a net-30 term to an invoice date, or add 280 days (40 weeks) to a last-period date to estimate a pregnancy due date.
The date calculator is completely free with no sign-up, and every calculation runs entirely in your browser. Nothing you enter is uploaded or stored, so your dates stay private.
Frequently asked questions
- Is this date calculator free to use?
- Yes, it is 100% free with no account, sign-up, or limits. You can add or subtract dates and count days between dates as many times as you like.
- How do I add or subtract days from a date?
- In the first mode, pick a start date, choose Add or Subtract, type a whole number, and select the unit (days, weeks, months, or years). The resulting date and its weekday appear instantly below.
- How do I find a future or past date from a given date?
- Use the first mode: Add moves forward in time and Subtract moves backward. Enter the number of days, weeks, months, or years and the exact target date appears at once, so you can see what date falls a set period from any starting date.
- Can I add weeks, months, or years instead of just days?
- Yes. After choosing Add or Subtract, pick the unit next to the number you enter. Month and year steps follow the calendar, so the result accounts for different month lengths and leap years automatically.
- How does it handle adding months to the end of a month?
- It clamps to the last valid day of the target month. For example, January 31 plus one month becomes February 28 (or February 29 in a leap year) rather than spilling into March.
- Can it count the number of days between two dates?
- Yes. Switch to the Days between two dates mode and enter both dates. It shows the total days, total weeks, a weeks-and-days split, and a years/months/days breakdown, even if you enter the dates in reverse order.
- Can I use this as a due date calculator?
- Yes. For any due date that sits a fixed period out, put the start date in the first mode and add the term, such as adding 30 days to an invoice date for net-30 or adding a number of weeks to a project kickoff. The result shows the due date and the weekday it lands on.
- How can I estimate a pregnancy due date (EDD)?
- This is a general date tool rather than a medical calculator, but you can approximate an estimated due date by adding 280 days (40 weeks) to the first day of the last menstrual period in the Add mode. For a clinically precise EDD, confirm with your healthcare provider.
- Does it show which day of the week the result falls on?
- Yes. Every result in the add-or-subtract mode includes the weekday of the resulting date, which is handy for scheduling deadlines, deliveries, or appointments so you know whether they land on a weekend.
- Does the calculation get affected by my time zone?
- No. All dates are treated as whole calendar days at local midnight, so there is no timezone drift and the number of days between two dates is always accurate.
- Is my data uploaded or stored anywhere?
- No. Every calculation happens locally in your browser using JavaScript. The dates you enter are never sent to a server, saved, or shared, so your information stays completely private.