About HerramientasGratis
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What it is
HerramientasGratis brings together 30+ online tools for everyday tasks: work out percentages and VAT, average your grades, count words, merge and split PDFs, compress images, generate strong passwords or convert units. They are all free, need no sign-up and are available in English and Spanish.
Alongside the tools there are practical guides that explain the reasoning behind each calculation, so you can check a result instead of relying on a black box.
Who is behind it
HerramientasGratis is an independent project created and maintained by Miguel Acevedo, a software developer. It does not belong to any company or media group. The goal is simple: tools that solve a specific task without pop-ups, forced sign-ups or uploading your files to a server.
How the tools are built
Every tool processes your data in your own browser whenever possible. When you compress an image, merge a PDF or format JSON, the file never leaves your device: no upload, no queue and no copy stored on any server.
The logic behind each calculation is kept separate from the interface and covered by automated tests with known cases. Every time a tool changes, those tests have to pass before it is published.
- Privacy first: nothing is uploaded unless you ask for it.
- Results with working: calculators show how they reach the number, not just the number.
- Accessibility: keyboard navigation, sufficient contrast and screen reader support.
How guides are written and reviewed
Guides are written from primary sources: official regulations, technical bodies such as NIST or the WHO, and reference works. Each guide links its sources at the end and shows the date it was last reviewed. Numerical examples are checked with the site's own tools.
Guides on tax, health or employment rules are for information only: they always note that the official figure is the one published by the relevant authority and that they do not replace professional advice.
How it is funded
The site is free and funded by advertising. Ads are labeled, kept away from download buttons and results, and we do not use pop-ups, full-screen ads or forced redirects. Advertisers have no influence over the tools or the guides.
Sister site
Our QR code generator lives at qr2us.com, with dynamic codes and scan statistics. The same account works on both sites.
Errors and suggestions
If you find a wrong result, a typo in a guide or a missing tool, write to us from the contact page. Calculation errors are fixed first and the fix is reflected in the review date.