How to use: Date Add / Subtract Calculator
Date Add / Subtract Calculator is a free online Date & Time Tools tool that add or subtract days, weeks, months from a date instantly in your browser. Paste your data, adjust the options and get the result in real time — no installation, no sign-up, and nothing is ever uploaded to a server.
Use Date Add / Subtract Calculator now →
Description
Add or subtract days, weeks, months from a date.
- Date & Time Tools
- Because everything is computed client-side, Date Add / Subtract Calculator is safe to use with sensitive data such as API keys, tokens or private logs.
How to use
Using Date Add / Subtract Calculator takes three steps:
- Paste your data into the input box (or load the example).
- Configure the options to match your target format or scenario.
- Copy, download or inspect the output — it updates live as you type.
Run
Examples
Add 90 days.
Input
2026-09-10
Output
Start: 2026-09-10T00:00:00.000Z Add 90 days Result: 2026-12-09T00:00:00.000Z Date: 2026-12-09 Time: 00:00:00 Unix: 1796774400 Weekday: Wednesday
This output was produced by actually running the tool, not written by hand.
Use cases
Common situations where Date Add / Subtract Calculator helps:
- Add or subtract days, weeks, months from a date.
Parameters
This tool has no options — it works on the input alone.
FAQ
What is Date Add / Subtract Calculator?
Date Add / Subtract Calculator add or subtract days, weeks, months from a date. It runs entirely in your browser, so your data stays private.
Is Date Add / Subtract Calculator free to use?
Yes. Date Add / Subtract Calculator is free, unlimited and works without registration or installation.
Does my data get uploaded?
No. All processing happens locally in your browser; nothing is sent to any server.
Good to know
- Everything runs client-side, so extremely large inputs are limited by your browser tab’s memory rather than by a server upload limit.