I'm growing a calculator site using multilingual SEO here's my strategy

I've been doing SEO for a while now and decided to build my own project to test strategies I use for clients.

The site is CalculatorSpan free online calculators for everyday use. Nothing fancy. But the SEO approach behind it is deliberate.

Why calculators?

High search volume. Low content complexity. Easy to scale across languages. A calculator page doesn't need 3,000 words to rank — it needs to solve one problem fast and be technically clean.

The multilingual angle

Most calculator sites only target English. I'm building Portuguese versions under a /pt/ subfolder, starting with Brazilian Portuguese traffic. Brazil has 215 million people. Portuguese search volume for calculator-type queries is huge and the competition is weak compared to English.

First Portuguese page is live: /pt/calculadora-de-horas-atras/

What I'm focused on right now:

Clean URL structure with language subfolders
Hreflang implementation for EN/PT pages
Building topical authority around time and date calculations
Backlinks through directory submissions and niche listings

Early results?

Too early to share numbers. Published this week. But the technical foundation is solid and the keyword gaps in Portuguese are very real.

If you're building a niche tool site, multilingual SEO is one of the most underused growth channels right now. Most people ignore non-English markets completely.

Anyone else doing multilingual SEO on a side project? What's worked for you?