PureTools
About PureTools
PureTools exists because looking up the conversion rate between meters and feet shouldn't require accepting cookies, dismissing a newsletter pop-up, watching a video ad, or lighting up a data center on the other side of the planet.
The premise
Most "free online tools" sites are advertising vehicles dressed up as utilities. The tool itself takes ten lines of JavaScript; the page wrapped around it weighs four megabytes, ships dozens of trackers, and exists primarily to harvest your data and your attention.
PureTools flips that. Every tool here is the actual product, not the bait. The pages are deliberately small. Nothing leaves your browser. The math runs on your machine, not on a server we'd have to pay for and could never promise to keep online.
Why not just ask AI?
The obvious alternative today is to type your task into a large language model. "What's 15% of €847?" or "Convert this PDF to JPG" or "What's my BMI?", these all work in ChatGPT. But they come at a cost most people don't think about.
A single ChatGPT query consumes roughly 10 times more energy than a Google search. Behind every answer is a warehouse of GPUs running at full load, drawing megawatts around the clock. That infrastructure exists to handle open-ended language tasks, nuance, ambiguity, synthesis, creativity. Routing a compound interest calculation through it is like driving a freight truck to buy a baguette.
The core insight behind PureTools is that math is stateless and immortal. The formula for a mortgage payment hasn't changed since the 18th century. The algorithm that converts kilograms to pounds will produce the exact same result in fifty years. These computations don't need to be retrained, don't need a data center, and don't need to phone home. A well-written JavaScript function running in your browser tab is faster, cheaper to operate, and for deterministic tasks, just as accurate as any AI, without burning the energy.
Use AI for what AI is uniquely good at: understanding ambiguous language, synthesizing sources, reasoning through open-ended problems. For calculations, conversions, and file processing, the right tool is a tool, not a language model wrapped around a calculator.
The real risk of uploading files
Every time you upload a file to a web service, a PDF to compress, a photo to convert, a video to cut, you hand a copy of that file to a stranger's infrastructure. What happens next is outside your control.
The risks are concrete, not hypothetical:
- Data breaches. The server storing your file can be compromised. Files processed by cloud tools have been exposed in breaches affecting millions of users. A file you uploaded to "compress a PDF" may sit in a storage bucket for months.
- Invisible retention. Many services retain uploaded files long after processing, for debugging, model training, or simply by inertia. Privacy policies rarely specify when deletion actually happens, if ever.
- Hidden metadata. A photo carries EXIF data: your GPS coordinates, device model, exact timestamp. A PDF can contain tracked changes, hidden author names, or text that appears redacted but is still readable in the raw file. Uploading a file you "just wanted to resize" can reveal far more than you intended.
- No server means nothing to breach. PureTools has no file storage. No S3 bucket, no database, no upload endpoint. The files you work with stay on your device from start to finish. There is nothing to hack because there is nothing there.
This is not a privacy promise written by a lawyer. It is an architectural fact. The code runs in your browser tab; the data never leaves it.
How it works under the hood
Every PureTools page is a static HTML file with vanilla JavaScript. No React, no Vue, no build pipeline, no API calls. When you open a tool, your browser downloads the page once and runs the logic locally, including for things people assume need a server, like image compression, PDF manipulation, video conversion and hash generation. For heavy operations like video and audio processing, we use WebAssembly, compiled binary code running at near-native speed, entirely inside your browser tab.
Practical consequences:
- Fast. No round-trips to a backend. Results appear as fast as your CPU can compute them.
- Offline-capable. After the first visit, the tools keep working in airplane mode.
- Private by construction. A site can claim it doesn't read your data. PureTools cannot read your data, there is no server to read it on.
- Permanently free. Hosting a static HTML file costs essentially nothing, which is why there is no freemium plan and no premium tier to upgrade to.
What we refuse to do
- No account creation. Nothing on this site requires an email address.
- No tool-input tracking. Typed text, uploaded files, generated passwords, calculator inputs, none of it is sent to analytics or any PureTools server.
- No session recording, no heatmaps, no Facebook SDK, no LinkedIn Insight Tag.
- No paywall. No "premium" tier hiding the useful features.
- No newsletter pop-up.
The only external service is a self-hosted analytics system that records anonymous page-level data: no IP address, no cookie, no personal identifier of any kind. No advertising network is active. Full details are in the Privacy Policy.
Who built this
PureTools is an independent project built by a developer who got tired of uploading personal files to services they didn't trust, and of watching AI assistants spin up GPU clusters to answer questions that a deterministic function answers in four milliseconds. No company, no VC funding, no growth team. Bug reports, feature requests and broken layouts are welcome through the contact page or at [email protected]. The source code is on GitHub.
What's next
More tools, same philosophy. The roadmap covers salary calculators, file format converters, audio editors and PDF utilities, all running locally, all free. New tools are prioritised based on search demand and on what people ask for. If something you need isn't here yet, send a feature request.