UnaHojaTools

Hi everyone,

I recently launched a small project called UnaHojaTools.

The idea is simple: a collection of practical calculators that solve common financial, real estate and legal calculations in Spain.

Current tools include:

• Mortgage payment simulator (monthly payment, amortization and an approximate APR/TAE)
• House flipping simulator (MAO, ARV, ROI/IRR and sensitivity analysis)
• Severance pay and settlement calculator (indemnización + finiquito)
• Working days calculator (count business days between dates)
• Unemployment benefit estimator (duration and monthly amount)
• Legal interest calculator (legal and late-payment interest)
• DNI / NIE and IBAN validators

Everything works instantly and requires no registration.

I built it because many of these calculations usually require spreadsheets or complicated formulas, and I wanted something much simpler.

Website: https://unahojatools.com

I’d love feedback on:
• usability
• ideas for new calculators
• growth or SEO suggestions

Thanks!