Three things worth
writing in about.

Every live calculator here publishes the formula it evaluates with each variable defined, a worked example with real numbers, the assumptions it makes and an explicit list of what it leaves out. Across 15 calculators that comes to 109 stated assumptions, 109 stated exclusions and 104 questions answered in full on the pages themselves. Those numbers are counted from the registry when this page is built, not typed into it.

So the honest first step for "why is this number what it is" is the formula block beside the result, and for "does this apply to me" it is the exclusions list underneath it. Both are on the page you were already looking at. The same material at one remove — how a figure is verified before it is published — is on how we calculate.

If the answer was there and you could not find it, that is itself a defect worth reporting. A derivation nobody can locate is not published in any useful sense, and where it happens the page is the thing that needs fixing.

This is the message worth the most here, because arithmetic is the whole proposition and a wrong result is a defect rather than a difference of opinion. What makes one actionable is that someone else can reproduce it, which needs four things:

1. Which calculator, by name or by the address of its page.
2. The inputs you used, as figures rather than descriptions. "A thirty-year loan at around six percent" cannot be re-run; "$300,000, 30 years, 6.25%" can.
3. The figure shown and the figure you expected. Both, not just the second — the gap between them is usually what identifies the cause.
4. Where your expected figure came from: a lender's statement, a regulator's published example, another tool, or your own working. This is the line that most often settles it, because the two numbers frequently answer slightly different questions.

That last point is worth expanding, because it is the commonest resolution and it is not a way of dismissing the report. A payment that excludes escrow will not match one that includes it; a schedule that compounds monthly will not match one that compounds daily; a ratio computed on gross income will not match one computed on net. Where that is the explanation, the useful outcome is not "you were mistaken" but a clearer label on the page, and that is a change to the page.

On sending figures: what you type into a calculator is computed in your browser and there is no endpoint it is sent to, but a shared link that already carries your inputs does carry them in its request line, like any URL. A scaled-down version of the same case — round numbers in the same proportions — reproduces almost every bug, so there is rarely a reason to send real ones. The privacy policy sets out the distinction in full.

What happens next is fixed rather than promised: the calculation is corrected first, a test is added that would have caught it, and then every page that quoted the old figure is updated. The editorial policy sets out that order and why it runs in that direction.

The name of a tool is the least informative part of a suggestion, because most names cover several different questions. "A retirement calculator" might mean how long a balance lasts at a given withdrawal rate, what contribution reaches a target by a date, or what a balance is worth in today's money after inflation. Those are three different engines with three different sets of assumptions, and the question is what decides which one gets built.

So the useful form of a suggestion is the question you wanted answered and the figures you had to hand when you wanted it. A suggestion in that form can be checked against what is already here — occasionally it turns out an existing tool answers it and the page simply does not say so, which is a labelling fix rather than a new calculator.

What cannot be promised is a date. Several engines here are finished and tested while their pages are unwritten, and that order is deliberate: the arithmetic is built and verified against independently worked values first, and the page is written second, because a page is a claim about arithmetic that already works. The four conditions a page has to meet before it ships are listed on the editorial policy page.

One kind of suggestion will be declined: a page whose purpose is to occupy a search result. If a proposed tool would answer the same question as an existing one in slightly different words, the right outcome is a better single page, not a second one.

There is no form on this page, and that is a design decision rather than an omission. A form has to post somewhere, and the absence of any endpoint that receives a calculation is the single most load-bearing fact about how this site handles your data. Adding a message endpoint to save you opening a mail client would weaken the thing worth more than the convenience.

What that means in practice is ordinary and worth saying plainly. A message you send is email: it sits with a mail provider, it is personal data from the moment it arrives, and it is readable by whoever maintains the site. Nothing about it is connected to your use of the calculators, because there is nothing recorded about that to connect it to. Your rights over that correspondence are set out on the privacy policy page, including having it deleted on request.

So the one practical caution is the one that applies to any email: do not send anything you would not want sitting in a mailbox. Account numbers, statements and documents are never needed to reproduce a calculation — four lines of figures are enough, and rounded figures are usually enough for those.

What will not be promised here is a response time, a review cycle or an acknowledgement. Those are commitments nothing on this site can measure, and an unmeasurable promise is worth less than saying so. What is promised instead is the order of operations above — the engine is corrected before the prose is, and each tool carries the date its formula was last reviewed so that a correction is visible rather than silent.

• Advice about your own situation. Nobody here is licensed or regulated to give financial, tax, mortgage or legal advice, and a correct calculation is not a recommendation. An answer to "should I refinance" would be advice from someone unqualified to give it, which is worse than no answer. The disclaimer sets out exactly where that line falls.
• Anything about an actual account. This site has no relationship with any lender, bank, card issuer or servicer, and no access to any account anywhere. A question about a real balance, payment or statement has to go to the institution holding it — they have the contract and the figures, and nothing here does.
• Data about you. There is no account to recover, no password to reset and no history to export, because none of those exist. An access request would return nothing about your use of the calculators, for the good reason that nothing about it is recorded.

None of those three is a support policy that could be relaxed later. Each follows from how the site is built, which is why they are stated here alongside the things that are welcome rather than buried in a footer.