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What to write about

A tool gave the wrong answer

This is the message we most want to receive, and the one we act on fastest. To make it actionable, please include the exact inputs you entered, the result the tool showed, and the result you expected, plus where your expected figure came from if it was another calculator, a bank statement or a textbook. Disagreements often turn out to be a difference in convention rather than a bug — for example whether a date range counts both endpoints, or whether an interest calculation compounds monthly or annually — and knowing your source lets us tell you which it is, and fix the page's wording if we were unclear.

A tool is broken on your device

Please tell us the browser and version, the operating system, and whether the page showed an error or simply did nothing. For the file tools it also helps to know the file's approximate size and format. Many issues are specific to one browser's handling of a particular image or PDF, so those details narrow it down quickly.

You want a tool that does not exist yet

Tell us the actual task, not just the tool name — knowing why you need it usually changes what the right tool looks like. Several utilities on this site were added because somebody described a problem we had not considered.

An advertisement is misleading or inappropriate

Advertising keeps the site free, but it should never be confusing or deceptive. If you see an ad that imitates a download button, obscures a tool, or promotes something plainly inappropriate, please send a screenshot and the page you saw it on. We can block individual advertisers and categories, and we do.

Privacy and data

Questions about what happens to what you enter are answered in detail in our privacy policy, which explains which tools run entirely in your browser and what the one server-side converter does with an upload. Anything the policy does not cover can go to privacy@grabnix.com.

Things we cannot help with

• Recovering a file. The browser-based tools never send your files to us, and the one converter that does receive an upload deletes it the moment the download finishes. There is no copy for us to retrieve — please keep your originals.
• Individual professional advice. We cannot tell you which loan to take, interpret a health measurement, or advise on your tax position. The calculators show how a figure is derived; acting on it is a conversation for a qualified professional who knows your circumstances.
• Guaranteeing a figure for an official submission. Always check a number against the institution that will actually use it before you file it.

Before you write

If the question is "which convention does this tool use", the answer is usually already on the tool's own page — each one states its formula, its assumptions and its limits underneath the calculator. It is worth a look first, and if the page did not make it clear, that itself is worth telling us about.