How We Build and Check These Tools

Who writes this

Started ToolForge in May 2026 and has built and maintained it since, writing every tool on the site and the documentation that goes with each one. There is no content team and no outside contributors: every tool and every page of writing on ToolForge comes from one person, which is worth knowing when you weigh up what you read here. Where a calculator touches money or health, the page states the formula it uses so you can check the arithmetic yourself rather than take it on trust.

Where the formulas come from

Of the 215 tools on the site, 88 are calculators. None of them invent a method. Each one implements a published, checkable formula, and the tool page names it. Three examples of what that means in practice:

• •BMI uses the standard definition — weight in kilograms divided by height in metres squared, or weight in pounds divided by height in inches squared, multiplied by 703 for imperial input.
• •BMR uses the Mifflin–St Jeor equation, which is the one most commonly recommended in current nutritional practice over the older Harris–Benedict formula.
• •Loan and EMI payments use the standard amortisation formula, and the schedule is generated by applying it month by month against a reducing balance rather than by approximating a total.

A formula being standard does not make its output advice. A BMI figure says nothing about body composition, a BMR estimate is a population average that your own metabolism may sit well away from, and a loan schedule ignores fees, insurance, and rate changes that a real lender will apply. These tools are for arithmetic. Decisions about your money or your health belong with a professional who knows your circumstances.

What leaves your browser, and what does not

Nearly every tool here runs as JavaScript on your own machine. When you compress an image, the file is read into a canvas element in your browser, re-encoded there, and handed back to you as a download. It is never sent to us, because there is nowhere on our side for it to go — the site is statically generated and holds no uploads.

Thirteen tools cannot work that way, because the answer lives on a machine that is not yours. Nine of them pass what you give them to a third-party service. This is the complete list, and each of these tools also says so on its own page:

The other four work differently, and the distinction is worth understanding. The Ping Tool, Port Checker, URL Redirect Tracer and Website Status Checker send a request from your browser straight to the address you typed. There is no intermediary and no API key: your own connection contacts that site directly, so the site you are checking sees your IP address, and nobody else sees anything. Because browsers restrict what a page may read from another origin, these tools report reachability and timing rather than full response detail.

Two more things leave your machine on any page, and neither is a tool: analytics, and advertising. Both are set out in the privacy policy, along with how to opt out of personalised ads.

How the writing on each tool page is produced

Every tool page carries an explanation of what the tool does, instructions that match its actual controls, and answers to the questions people ask about it. That text is written against the code, not around it: the steps are checked against the real inputs, and a claim about a format, a limit, or a formula only goes in if the implementation actually does it.

Two rules hold the standard in place. Nothing is templated — pages are written one at a time rather than mail-merged with the tool name swapped in, and an automated check refuses any sentence that appears on two different tool pages. And no page claims that your data stays local unless it genuinely does; the tools in the table above say plainly that they send data out.

Each page shows the date its content was last reviewed. That date changes when the text is genuinely re-read, not when the site is redeployed.