# Date Add/Subtract Calculator

> Add or subtract days, weeks, months, or years from any date. Handles month-end and leap-year rollovers.

URL: https://uttir.com/date-add-subtract
Categories: date-time-tools, calculators
Privacy: All math runs in your browser. No date leaves your device.

## About

Add or subtract any number of days, weeks, months, or years from a starting date. Useful for figuring out deadlines ("30 days from today"), anniversaries, project timelines, and just about any date math you would otherwise do on a paper calendar.

Months and years roll over correctly: January 31 + 1 month = February 28 (or 29 in a leap year). Days and weeks do not care about month length.

## How to use

1. **Pick a starting date** — Defaults to today. Edit it freely.
2. **Choose a unit and amount** — Days, weeks, months, years, hours, or minutes. Negative values go backward.
3. **Read the result** — The target date and the number of days between start and target.

## Examples

### 30 days from today

A standard return-window deadline.

Output:

```
Date + 30 days
```

### 6 months back

For figuring out a 6-month lookback window.

Output:

```
Date − 6 months
```

## FAQ

### How are months handled?

Months are added by name, so Jan 31 + 1 month = Feb 28 (or Feb 29 in a leap year). The tool never produces an invalid date — it rolls over to the last valid day of the month when needed.

### Are the calculations timezone-aware?

Dates are treated as calendar dates in UTC, so you get the same answer no matter where you are in the world. If you need timezone-aware math (e.g. business days), that is a different tool.

### How are time zones handled?

The tool uses your browser's local time zone for the input and output. If you need to add days in a specific time zone, set the time zone on the input — the output will be in the same time zone.

## Related tools

- [Date Calculator](https://uttir.com/date-calculator) — Count the days between two dates, or add and subtract days from any date.
- [Age Calculator](https://uttir.com/age-calculator) — Find the exact age in years, months, and days — plus totals and the countdown to the next birthday.
- [Unix Timestamp Converter](https://uttir.com/unix-timestamp-converter) — Convert Unix timestamps to readable dates and back, with a live current-time readout.

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For the full HTML page with the live tool, visit https://uttir.com/date-add-subtract.
This file is the markdown rendering at https://uttir.com/date-add-subtract.md. See https://uttir.com/llms.txt for a site-wide summary.