About MoneyOtter
Free money calculators that do their work in your browser, show every step, and are honest about what they don’t know.
Why it exists
Money questions are often simple arithmetic wrapped in confusing conventions. Is a 5% savings rate the same as 5% on a loan? What does overpaying a mortgage actually save? What would 100 from 1990 buy today? Most calculators answer with a single number and no explanation, and many are built for one country, one currency and one way of quoting rates.
MoneyOtter gives you the number and the working behind it, in any currency, using the conventions banks and lenders really use. Our mascot, Pebble, is an otter: otters are famously unflustered, and they keep a favorite stone tucked away for later. That’s the mood we’re after — calm, clear and careful with what matters.
Who runs it
MoneyOtter is operated by Infinity Square Labs Ltd, a company registered in England and Wales (company number 16880965), with its registered office at 483 Green Lanes, London, N13 4BS, United Kingdom. We’re a small independent studio that builds free, privacy-first web tools. We are not a bank, lender, financial adviser, broker or tax adviser, and we don’t present ourselves as one.
How it’s funded
Pages carry a small number of clearly labelled ads, which never appear inside a calculator, between your inputs and your results, or on legal pages. That keeps every calculator, export and schedule free. We don’t take affiliate or referral payments for loans, cards, mortgages, investments, pensions, insurance or money-transfer services, and we don’t recommend financial products.
How we keep the figures accurate
- Exact arithmetic. Money is calculated with decimal arithmetic and rounded the way each calculator documents, not with the floating-point shortcuts that cause penny errors.
- Official data. Exchange rates come from the European Central Bank and price indexes from national statistics offices, stored unmodified with their sources and licences.
- Known answers. Every calculator is tested against worked examples before it is published.
- Country tax tools only when verified. A country’s take-home calculator is published only after it passes official test cases and an independent cross-check. The calculators have not been independently reviewed by a professional adviser, and we say so.
- Visible changes. Changes that affect figures are dated in the changelog.
Mistakes are still possible. If you find one, email errors@moneyotter.com. The methodology explains every formula, and the disclaimer explains what the results are and aren’t.
Get in touch
Questions, suggestions and corrections are welcome on the contact page.