Calculadora

The short version: we got tired of UK calculator sites that covered the mortgage and the PAYE but nothing else, and Brazilian sites that understood FGTS but could not help a reader on a UK payslip. Calculadora sits between the two — one home, one search box, 99 calculators, bilingual throughout.

Every calculator here has three things baked in from day one: a pure, unit-tested function so the numbers match the spec sheet; a plain-English (and plain-Portuguese) explanation of what the answer means and where it breaks down; and links out to the primary source (GOV.UK, HMRC, NHS, Receita Federal, Banco Central do Brasil) so you can verify a threshold or rate against the horse's mouth before you act on it.

We do not sell leads, we do not publish advertorials, and we do not track you across pages with third-party pixels. The point of the site is to answer the question you arrived with, quickly, then get out of the way. If that sounds obvious, compare it with the five top-ranked calculator sites on any financial query today — the contrast is the whole business model.

Search volumes for 'calculator', 'calculadora' and 'free calculator' run into tens of millions per month globally. A tiny fraction of that traffic lands on pages that actually explain the maths. Our opinion is that the explanation is the product. The widget at the top of every page is just where the explanation starts.

In the UK market the equivalent intent splits across "free calculator", "calculator UK", "online calculator" and specific queries like "salary calculator UK" or "pension calculator free". We treat both intents as first-class. The English version of each page uses UK-native examples (£, stones, mpg, gas marks, HMRC bands); the Portuguese version uses Brazilian and Portuguese-language examples (R$, kg, km/L, Receita Federal tables).

Free does not mean sloppy. Every tool in the Calculadora catalogue is benchmarked against either an official source (GOV.UK, HMRC, ACSM, WHO, NHS) or a peer-reviewed formula. When thresholds shift — for example in April when the UK tax year rolls over, or after the Brazilian Budget vote — we update within 24 hours of the announcement and stamp the page with the current version.

There is no usage cap. Run the same calculator a hundred times, share the URL with a colleague, embed a screenshot in a presentation. If a result is important, treat the page URL as your working paper: it regenerates the exact same answer for anyone who clicks it, because the inputs live in the URL's query string.

A small number of specialised calculators are UK-only (stamp duty, ISA allowance, council tax) or Brazil-only (FGTS, INSS, 13º). Those pages still render in both languages so a Brazilian reader in London can understand stamp duty without the jargon, and a British partner in São Paulo can follow the 13º conversation. The terminology is explained each time.

Everyday crossovers the site handles natively: converting a UK gross salary to a Brazilian-equivalent net after IRRF; comparing a UK ISA allowance in pound terms against a Brazilian CDB-DI return in real terms; estimating the GBP-BRL remittance cost via Wise vs. a high-street bank; working out whether a buy-to-let in Rio is worth financing via a UK lender; running both sides of a currency hedge before a business invoice lands.

The bilingual angle is not a marketing gimmick. It shows up in the calculators themselves: the currency-converter-gbp-brl tool pulls live ECB and Bank of England rates; the take-home-pay tool computes both a UK net-of-PAYE-and-NI figure and a parallel Brazilian INSS+IRRF figure for readers earning across borders; the pension tool explains how UK workplace pensions interact with Portuguese and Brazilian social security for dual residents.

We also run a UK-Brazil content desk on the blog. Pieces cover topics like 'How to move your savings from Nubank to Chase while keeping the tax straight', 'Opening a Brazilian brokerage as a UK resident', 'What stamp duty looks like for a Brazilian buying in Camden', and 'How to read a Wise transfer receipt for Receita Federal declaration'. The calculators feed the articles, and the articles deep-link back into the calculators where they add numbers.

For readers who are only on one side — a Brazilian in Belo Horizonte who has never set foot in the UK, a Londoner with no ties to Brazil — the site still reads naturally. The bilingual scaffolding sits behind the scenes; the page you land on is in your language with examples from your context.

Pick the category that matches the question. If the question spans two categories — 'how much tax on my overtime' — either landing point works, and the related-calculator grid on each page links the others.

Every calculator is a pure TypeScript function living in `lib/calculadoras/*`. Each function ships with a unit-test suite that runs in CI on every commit — a change to the PAYE bands fails the test if the output does not match the new bands within a 1p tolerance. The same function runs in the browser and in the test runner, so there is no drift between 'what we explain' and 'what we compute'.

Rates, thresholds and official figures are stored in dated tables in `lib/calculadoras/<calculator>.ts`. When HMRC publishes a new personal allowance, the Budget lands a new stamp duty band, or the Banco Central changes the INSS ceiling, one commit replaces the table, adds the new effective date, and propagates across every page that uses it. The `dateModified` stamp on the page updates automatically.

Editorial review sits on top. Our reviewer, Laura Whitmore, is a former HMRC officer and writes the finance explainers personally. Rafael Costa, our Brazilian tax correspondent, reviews the INSS / IRPF / FGTS pages. Dr Maya Patel reviews the health calculators. Every page carries a byline, a reviewer credit, a publication date, a modification date, and a link to the author's profile page — the E-E-A-T scaffolding that Google documents in the Search Quality Evaluator Guidelines.

We also publish a corrections policy. If a reader finds an out-of-date rate or a miscomputed bracket, they email the editorial desk and we patch it. The corrections page lists every material change with date, affected calculator and the correction itself — same format as The Guardian and the Financial Times run for their numeric journalism.

The full editorial policy, corrections policy, author bios and data sources are linked from the footer of every page. None of this is cosmetic. Google's 2023 and 2024 Helpful Content Updates specifically penalise YMYL (Your Money Your Life) pages without clear authorship and sourcing. Our editorial backbone is designed for that standard, not for a keyword-density target.

Sofia in Manchester, moving from a band 6 to a band 7 NHS role. 'My trust's online payslip preview was wrong by £80 a month. Your PAYE calculator showed me the right figure, and I could explain it to my ward manager with the bands on the page. Got it corrected inside a week.'

Bruno in Belo Horizonte, freelance developer billing a UK client. 'I needed to show my accountant what the Wise fees actually cost me in reais. Currency-converter-gbp-brl with the ECB mid-market rate, plus the all-in-fee line, was the first page I had seen that quoted both the interbank and the realistic price.'

Chisom in London, first-time buyer on a £420k flat. 'Stamp duty calculator told me I owed £6,500 even after first-time-buyer relief because the flat was above £425k. The mortgage calculator showed me the monthly on a 4.85% 5-year fix, and the page explained how the affordability multiple works. I took screenshots into the broker meeting.'

Rafael, UK-based Brazilian finishing a maths GCSE at 32. 'I learned Bhaskara at school in Portuguese and had no idea what the UK system calls it. Your Bhaskara page told me it is the quadratic formula in the UK curriculum, and the worked example was the first one I had seen that used the same notation my old textbook does.'

Hanna in Lisbon, dietician triangulating a patient's macros. 'I ran the BMR on three methods, the TDEE on two activity levels and the macros across 40/30/30. Having it on one page, with the formula visible, meant I could show the patient why the target was 1,850 kcal rather than 1,500.'

Every one of these readers arrived from search, ran the calculation on the page, and left with the URL bookmarked. Nothing about the workflow is exotic — it is what a calculator site is for. What is unusual is that the calculation was right and the explanation was readable.

This is not a dictionary. It is a rolling list of the 40-odd terms that readers ask about most often. If a term is missing, email the editorial desk and we will add it — same day on weekdays, within 48 hours on weekends.