About the Calculator

The Calculator is a full-featured browser calculator for everyday arithmetic. It supports the standard operations — addition, subtraction, multiplication, division, percentages, and decimals — with a keyboard-style interface and keyboard input.

It runs instantly in your browser with no sign-up, so it is always available for quick maths without opening a phone app or searching the web.

How to use the Calculator

1. 1Open the Calculator tab.
2. 2Click the buttons or type on your keyboard to enter numbers and operators.
3. 3Press = (or Enter) to see the result.
4. 4Use C or Escape to clear and start a new calculation.

How the Calculator works

For the Calculator specifically, it is a full-featured browser calculator for everyday arithmetic. Productivity tools are a mix of browser-platform utilities that process input locally, with one exception. The Calculator evaluates arithmetic expressions in the browser. The Password Generator uses the Web Crypto API’s crypto.getRandomValues, a cryptographically secure random source, rather than Math.random — the resulting passwords are suitable for real accounts and are never transmitted or stored, so copy the result into a password manager immediately. The Timer and Stopwatch use setInterval and Date.now for timing; the timer keeps running while the tab is open in the background but stops if the tab is closed, so keep the tab open for long countdowns. The To-Do List holds tasks in component state for the session only — browser data can be cleared, so for long-term storage copy your list or use a dedicated task manager. The Markdown Editor parses standard Markdown syntax (headings, bold, italic, lists, links, code blocks) to HTML with regular expressions and offers split, edit, and preview modes. The QR Code Generator is the exception: it sends the content you encode — a URL, text, or contact details — to a third-party rendering service in the request URL, which draws the code server-side and returns a static PNG with no click-tracking. Because the content travels in the request URL, avoid encoding sensitive personal data. Generated QR codes are static images: the destination cannot be changed after printing, so to update a code later, encode a link you control and redirect it.

How this tool handles your data. Most tools in this category run entirely in your browser. The QR Code Generator sends the content you encode to a third-party rendering service in the request URL, so avoid encoding sensitive data. The Password Generator uses the Web Crypto API and never transmits the passwords it produces. Session tools such as the To-Do List keep data only while the page is open.

Supported formats & limitations. The Calculator supports standard arithmetic with keyboard input. The Password Generator uses the Web Crypto API. The To-Do List keeps tasks in your browser session only — copy them if you want a record. QR codes are static images with no click-tracking; generate at 512×512 or larger for print.

Practical workflow. In practice, you work through a short sequence: 1. Open the Calculator tab 2. Click the buttons or type on your keyboard to enter numbers and operators 3. Press = (or Enter) to see the result 4. Use C or Escape to clear and start a new calculation. It is well suited to quick sums, percentages, and splits without a phone app; checking figures while budgeting or invoicing; everyday maths during work or study.

Best practice. Generate a unique password for every account and store it in a password manager, and keep your to-do list short and specific so the most important items stay visible.

Tips & common pitfalls. With the Calculator in particular, quick sums, percentages, and splits without a phone app. Generate a unique password for every account and store it in a password manager, and keep your to-do list short and specific so the most important items stay visible. The timer keeps running while the tab is open in the background but stops if you close it, so keep the tab open for long countdowns. For the QR Code Generator, avoid encoding sensitive data because the content travels to a third-party rendering service in the request URL. Session tools like the To-Do List clear when the page closes.

Troubleshooting

The first thing to know about the Calculator: number keys, operators, Enter for equals, and Escape to clear all work alongside the on-screen buttons. If the timer stops, the tab was closed — keep the tab open for long countdowns, since timing runs only while the page is active. If a generated password is rejected by a site, increase the length or confirm the required character types are ticked. If the to-do list clears, it is session-only — copy your list before closing the tab. If the QR code will not scan, regenerate at 512×512 or larger with a white margin, and avoid encoding sensitive data because the content travels to a third-party rendering service. If the calculator gives an unexpected result, clear and re-enter the expression; it does not keep history. If markdown preview looks wrong, confirm you used standard syntax.

Common use cases

• Quick sums, percentages, and splits without a phone app.
• Checking figures while budgeting or invoicing.
• Everyday maths during work or study.

Frequently asked questions

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