Frequently Asked Questions

Every tool has its own page. tool-annuity-calculator.html opens the annuity calculator directly, which means tools are bookmarkable and shareable. From there the ribbon bar, the search box and the directory on the hub page all move you to another tool, and the status bar at the bottom always shows which tool is active.

Use the search box in the top bar. Press Ctrl+K (or ⌘+K, or just /) to jump to it from anywhere, then use the arrow keys to move through results and Enter to open one.

Search matches tool names, descriptions, group names and each tool's own keyword list, including translated spellings — searching hipoteca, prêt or darlehen finds the mortgage calculator.

Yes. A tool is initialized the first time you open it and then kept in the page, so its inputs, chart and scroll position stay exactly as you left them when you switch away and come back. Only a full page reload clears them.

No. They are informational arithmetic based entirely on the figures and assumptions you supply. Nothing here is a recommendation, and no tool accounts for taxes, fees, insurance detail, early-repayment penalties, rate changes or market volatility. Verify anything you intend to act on with a qualified professional.

It spreads the property tax rate you enter across the loan balance and divides the annual insurance figure by twelve, then adds HOA dues to reach a monthly PITI total. Rates are held flat for the life of the loan, so it does not model reassessment or a jump in your insurance at renewal.

Both use the same mathematics from different directions. The compound interest tool projects forward: given what you put in, how much it could become. The annuity tool works in whichever direction you choose — it can solve for the future value, the present value, or the level payment required to reach a target, which is the shape of a loan, a lease or a pension.

If you have a starting balance plus regular deposits and want to know the end result, use compound interest. If you have a fixed regular payment and want to know what it is worth now or later, use the annuity calculator.

Deposits or payments made at the start of a period earn interest for that whole period; ones made at the end do not. Moving everything one period earlier is worth exactly one extra factor of 1 + rate/periods — that is the whole difference between an ordinary annuity and an annuity due.

Almost always because the underlying assumptions differ. Check that you are comparing like with like on the interest rate — a quoted "7%" may be nominal with monthly compounding or an effective annual rate — and note that when your contribution frequency differs from your compounding frequency, this tool assumes contributions are spread evenly across compounding periods rather than arriving on one exact day.

Real returns also move with the market. The projection holds the rate constant, which is a modelling convenience, not a forecast.

The extra-principal field covers voluntary overpayments: it shortens the term and the schedule shows the interest you saved as a result. A rate change mid-way is not modelled — if you expect to refinance, run the calculator again with the new rate and compare.

Nowhere. Every tool is plain JavaScript running in your browser, and there is no upload endpoint in the codebase for the values to travel to. A loan amount, a JSON payload or a generated password stays on your machine and is discarded when you close or reload the tab.

The full Privacy Policy sets this out in detail, including the two preferences saved in localStorage and how to clear them.

No. It is generated with the browser's cryptographic random number generator, shown on screen, and discarded on reload. Nothing is written to storage or sent over the network. For anything that matters, use a dedicated password manager instead.

Until you choose a language yourself, the site picks one from your browser's language preferences, matching whichever of your preferences it supports — en-US, en-GB and plain en all count as English, and if your first preference is a language we do not have it moves on to the next. English is used when none of your preferences are supported.

Hover over the language selector to see why it chose what it chose. Picking a language from the language selector, saves and persists the preference for the current browser.

Yes, once you choose one manually. It is saved in your browser's local storage and in a small first-party cookie, and both are read on your next visit so the choice survives clearing either one. Nothing else is stored.

A language detected automatically is not written to storage, so if you later change your browser's preferences the site follows them. Clearing site data resets the choice.