About PropCalc

Our Mission

PropCalc was built to give real estate investors — from first-timers to seasoned professionals — access to the same analytical tools that were previously only available through expensive software, complex spreadsheets, or paid consultants. We believe that better analysis leads to better decisions, and better decisions lead to better financial outcomes.

Real estate investment is one of the most powerful wealth-building strategies available, but it is also one of the most complex. Tax rules vary by country, mortgage terms differ by market, and the difference between a good deal and a bad one often comes down to a few percentage points. PropCalc gives you the numbers you need — instantly, for free, in your language, with your country's rules.

Whether you are evaluating your first fix-and-flip in Portugal, planning a BRRRR strategy in Spain, comparing rental yields across European markets, or simply trying to figure out how much house you can afford in Germany — PropCalc has a calculator for you. Our platform covers the full lifecycle of a real estate investment: from initial affordability and purchase costs, through financing and renovation, to rental income, capital gains, and eventual sale.

What Makes PropCalc Different

Most online real estate calculators are either too simple (a basic mortgage payment calculator) or too expensive (professional software costing hundreds of euros per month). PropCalc occupies the middle ground: professional-grade tools, completely free, with no registration required.

Our key differentiators are:

• Multi-country support: Every calculator supports Portugal, Spain, Germany, France, the UK, and the US with country-specific tax rates, mortgage rules, and market parameters.
• 6 languages: All calculators are available in English, Portuguese, Spanish, German, French, and UK English, with localised currency symbols and number formats.
• Sources and scope: Priority calculators display their official sources, review date and applicable market so assumptions can be verified before use.
• Educational content: Every calculator includes a detailed explanation of the methodology, a "How It Works" section, and a FAQ with practical examples.
• Privacy by design: All calculations run in your browser. We never store or transmit your financial data to any server.

Our Principles

Our Methodology

All PropCalc calculators are built on publicly available, official data sources. Tax rates are sourced from national tax authorities (Autoridade Tributária in Portugal, HMRC in the UK, IRS in the US, etc.). Mortgage parameters are based on central bank guidelines and typical market conditions. Property market data is sourced from national statistics institutes and real estate industry reports.

Tax rates, mortgage parameters and market data can change. Each calculator identifies its official sources, review date and scope. If you notice a discrepancy with an official source, please contact us so that we can review the calculation and its assumptions.

Our formulas follow industry-standard methodologies: mortgage calculations use the standard annuity formula; rental yield calculations follow RICS (Royal Institution of Chartered Surveyors) definitions; capital gains calculations follow each country's tax code. Where there is ambiguity or multiple valid approaches, we document our choice and the alternatives.

Our Calculators

PropCalc currently offers 52 calculators across 6 categories, covering the full lifecycle of a real estate investment.

Countries We Cover

PropCalc currently supports real estate investment analysis for the following countries, with country-specific tax rates, mortgage rules, and market parameters:

The Person Behind PropCalc

My name is Luís Castanheira. I'm a civil engineer based in Portugal. This past year I started working at a construction company involved in real estate development — and that experience sharpened my interest in property investment in a way I hadn't expected. Seeing deals being structured up close made me want to understand the numbers deeply, not just intuitively.

Like many people my age, I'm driven by a goal that's becoming increasingly common: financial freedom. Not overnight wealth, but the kind of steady, compounding independence that comes from smart investments — in the stock market, in ETFs, and in real estate. I believe that combining both worlds is one of the most powerful strategies available to ordinary people today.

PropCalc was born from that journey. I built these tools for people who are at the same stage I am — taking their first steps, wanting to run the numbers before they commit, and not wanting to pay for expensive software to do it. But also for more experienced investors who need fast, reliable calculations adapted to the real fiscal rules of Portugal and Europe. Free, no login, no friction — just the numbers.