About UtilWebPro
Last updated: 3 July 2026
Who is behind it
My name is Bernabé Nicolás García and I build and maintain UtilWebPro from Murcia (Spain). I have spent more than two decades working with databases and software development in environments where a wrong calculation has real consequences, and that is the standard I try to apply here: every tool should do exactly what it says — and you should be able to understand how it does it.
How the tools and the texts are built
Every calculator goes through the same process before publication:
- The formula, from the original source. Calculations are implemented from the official standard or definition: the ISO 7064 modulo-97 algorithm for IBANs, the Spanish Interior Ministry's official NIF letter table, the French amortisation system for loans, the WHO reference ranges for BMI, or established spelling conventions for writing out numbers.
- Testing against known cases. Before going live, each tool is checked against reference results (sample banking-sector IBANs, test ID numbers, loan payments cross-checked with official simulators).
- Explanations with real examples. Every page includes the formula, a step-by-step worked example and the questions people actually ask, because the site's goal is not just to output a number but to help you understand where it comes from.
- Review whenever the rules change. Content tied to regulation (VAT rates, social contributions, withholdings) is reviewed periodically and carries warnings when temporary measures may vary.
Privacy by design
All tools run entirely in your browser using JavaScript. The numbers, texts, images or documents you enter are never sent to any server or stored anywhere: you can verify it by disconnecting from the internet once the page has loaded — everything keeps working. The site is funded exclusively by Google AdSense advertising, clearly labelled as such.
Limits of the tools
UtilWebPro's calculators are informational and educational. Results with tax, financial, employment or health implications (VAT, mortgages, net salary, BMI…) are orientative and do not replace professional advice or the information provided by official bodies, such as the Spanish Tax Agency or Social Security.
Contact
Found a mistake, missing a tool, or want to suggest an improvement? Write to me at bernabe.nicolas@gmail.com. I read every message, and a good share of the site's improvements have come from suggestions by the people who use it.
See also the legal notice, the privacy policy and the cookie policy.