# Calculator24

> Basic, scientific, notepad, programmer, date and unit-converter modes in your toolbar or side panel. Works offline.

Canonical page: [https://chrome-stats.com/d/calculator24](https://chrome-stats.com/d/calculator24)

## Overview

- **ID:** `calculator24`
- **Platform:** Firefox
- **Type:** Firefox add-on
- **Status:** Available
- **Publisher:** Def24 Inc.
- **Category:** other
- **Daily users:** 1
- **Weekly downloads:** 1
- **Version:** 0.1.0
- **Last updated:** 2026-08-10
- **First published:** 2026-08-07
- **Size:** 205 KB
- **Data as of:** 2026-09-08
- **Store listing:** [Firefox Add-ons Store](https://addons.mozilla.org/firefox/addon/calculator24/)
- **Website:** [https://calc24.org](https://calc24.org/)
- **Privacy policy:** [https://addons.mozilla.org/firefox/addon/calculator24/privacy/](https://addons.mozilla.org/firefox/addon/calculator24/privacy/)

## Description

Calc24 puts a real calculator in your browser toolbar. Open it as a popup, or dock
it in the side panel and keep it beside your work while you browse.

Six modes, one calculator:

• Basic — the everyday keypad, with memory and a running result as you type.
• Scientific — trigonometry, logarithms, powers, roots, factorials, degrees or
  radians.
• Notepad — work down a page of lines. Name a value and reuse it, refer to the
  line above with "ans" or the running sum with "total", and edit any line to
  recompute everything below it.
• Programmer — hex, decimal, octal and binary side by side, with AND/OR/XOR/NOT,
  shifts and rotates, 8- to 64-bit words, and a bit grid you can click.
• Date — the days between two dates, or a date shifted by years, months and days.
• Converter — mix units in one expression: "5 ft + 3 in in cm", "2 GB / 15 Mbps",
  "120 km / 2 h in mph". Currency too.

Everything else you would expect: multiple calculator tabs you can name and fork,
history and pinned results you can copy or reuse with one click, and six themes.

Your calculations stay on your device. There are no accounts, no tracking, and
the only network request the extension makes is for currency exchange rates —
and the converter still works without it, on rates bundled with the extension.

Open source calculator, also on the web at <a href="https://prod.outgoing.prod.webservices.mozgcp.net/v1/3a421a8c6f83b8d7944f8a4d037f6b5fd084ace05441e38fdc9160e4a2c65c20/http%3A//calc24.org" rel="nofollow">calc24.org</a>.

## Rankings

- #89,203 — Overall
- #86 — programmer
- #136 — calculus
- #173 — calculator

## Permissions and access

### Permissions

- `storage`

### Host permissions

- `https://open.er-api.com/*`

## Safety

- **Risk impact:** Low risk impact
- **Risk likelihood:** High risk likelihood

### Analysis details

- Request access to the following domains: er-api.com
- This extension was recently updated in the past month. New updates may not be stable or safe.

> Some risk analysis details are omitted from this free response. [Upgrade to view the full analysis](https://chrome-stats.com/pricing).

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Source: [Chrome-Stats](https://chrome-stats.com/d/calculator24)