# Add days to a date

> To add days to a date, count forward from the start date: 30 days after 11/06/2026 is 12/06/2026, a Sunday. The calculator also adds or subtracts weeks, months, and years. Adding 1 month to 01/31/2026 lands on 02/28/2026, because February has no 31st, so the result snaps to the last day of the month.

Source: https://www.calterix.com/en-us/calculator/add-days/ · Updated 11/06/2026 · en-US

## How to add days to a date

Adding days and weeks is plain counting on the calendar: 1 week is 7 days, and the tool steps through months of 28, 29, 30, and 31 days one by one. Adding months or years keeps the same day of the month and only adjusts when that day does not exist in the target month.

```
New date = start date ± amount (days, weeks, months, or years)
11/06/2026 + 30 days = 12/06/2026 (Sunday)
```

To measure the gap between two dates you already know, use the [days between dates calculator](https://www.calterix.com/en-us/calculator/days-between-dates/). To see how many days are left until a holiday or a deadline, try the [countdown calculator](https://www.calterix.com/en-us/calculator/countdown/).

## Dates X days from today

| Days added to 11/06/2026 | New date | Day of the week |
| --- | --- | --- |
| 7 days | 11/13/2026 | Friday |
| 14 days | 11/20/2026 | Friday |
| 30 days | 12/06/2026 | Sunday |
| 60 days | 01/05/2027 | Tuesday |
| 90 days | 02/04/2027 | Thursday |
| 180 days | 05/05/2027 | Wednesday |

Start date: Friday, November 6, 2026. Change the start date to count from any other day.

## Month ends, leap years, and deadlines

| Math | New date | Day of the week |
| --- | --- | --- |
| 11/06/2026 + 2 weeks | 11/20/2026 | Friday |
| 01/31/2026 + 1 month | 02/28/2026 | Saturday |
| 02/29/2024 + 1 year | 02/28/2025 | Friday |
| 03/01/2026 − 1 day | 02/28/2026 | Saturday |

Month ends and leap days snap to the last valid day.

- Day 31 plus 1 month: when the next month is shorter, the result is that month's last day (01/31 becomes 02/28, or 02/29 in a leap year).
- February 29 plus 1 year: in a non-leap year, the result is February 28.
- Deadlines counted in days usually leave out the start day. Because the tool adds to the start date, the start day itself is not counted.
- "Business days" are not skipped here. Weekends and holidays are counted like any other day.

> Legal, contract, warranty, and return deadlines each follow their own counting rules. Check the wording of the document, or ask the other party, before relying on a date.

## Frequently asked questions

### What is the date 90 days from today?

Enter today as the start date, type 90, and keep the unit on days. From Friday, November 6, 2026, 90 days later is Thursday, February 4, 2027.

### How do I add days to a date?

Type the start date, choose Add, enter the number of days, and read the new date. Adding 30 days to 11/06/2026 gives 12/06/2026.

### How do I subtract days from a date?

Choose Subtract and enter the amount. Subtracting 1 day from 03/01/2026 gives 02/28/2026.

### What date is 30 days from today?

Use 30 days as the amount with today as the start date. From November 6, 2026, the answer is December 6, 2026, a Sunday.

### What happens when I add 1 month to January 31?

The result is the last day of February, since the 31st does not exist there. In 2026 that is 02/28/2026.

### How do I add weeks or months to a date?

Switch the unit to weeks or months. A week is 7 days, and a month keeps the same day number in the following month when that day exists.