About MyLoanMath

Who runs this site

MyLoanMath is built and maintained by Ishmael, an accountant. The site exists because too many financial calculators produce a number and refuse to show their working — and when the number matters, the working is the part you need. Everything here is written to be checked: the methodology page names the source behind every figure, and the corrections log records every mistake found so far, dated, with the size of the error in dollars.

Working in accounting is what makes the omissions obvious. It is why the tax calculators tell you when a state figure is an approximation instead of quietly rounding past it, why a refinance is reported on lifetime cost as well as the flattering break-even month, and why the rent-versus-buy tool puts every assumption on screen rather than burying a 5% appreciation rate in the code and calling the result an answer.

Educational, not advice

This site is educational. It is not financial advice, tax advice, or accounting advice, and using it does not create a client relationship of any kind. Nothing here is a recommendation to take out a loan, refinance, buy or rent a home, choose a filing status, or make any other financial decision.

The distinction is a real one rather than boilerplate. A calculator can tell you what a payment works out to, or what a tax bill comes to on a given set of inputs — that is arithmetic, and it is checkable. Advice means telling you what you should do, which depends on your full circumstances, your other obligations, and your goals, none of which this site knows. Those figures are a starting point for a conversation with a qualified professional who can see your whole position, not a replacement for one. For a decision with real money attached, speak to an accountant, tax adviser, or licensed financial adviser directly. The full terms are on the Terms & Disclaimer page.

How the numbers here are produced

Every figure on this site is verified against a primary source before it is published: IRS publications and Revenue Procedures for US federal tax, CRA guidance for Canada, and each state or province's own revenue authority or statute for sub-national tax. Where only secondary sources exist for a figure, they are cross-checked against one another and the limitation is disclosed inside the calculator's own result rather than in fine print somewhere else.

Calculation logic is checked by recomputing a worked example by hand and comparing it against the code — not by reading the code and judging it correct. Changes are then tested through the rendered page, and every other calculator is re-run afterwards to catch anything the change broke elsewhere. Pending legislation is never modelled as though it were law; when a bill would change a figure, its enactment status is checked before anything moves.

Mistakes are published, not quietly patched

Financial calculators get things wrong. Most sites correct them silently. This one keeps a dated public record on the Corrections & Changes page, stating what was wrong and by how much in dollars wherever the error can be quantified. A site that has never admitted an error is not a site that has never made one, and the log is the only way for a reader to judge which kind they are looking at.

Where a calculation is an approximation rather than an exact answer, the calculator says so in its own output. The Methodology & Sources page lists the specific source behind each tool, along with what is still incomplete.

How this site makes money

MyLoanMath is free and supported by advertising. Nothing commercial influences a calculation, a recommendation, or which tools exist: there are no affiliate links to lenders, banks, insurers, or tax preparers anywhere on this site, and no result is shaped by anything other than the arithmetic. There is no paid placement and no sponsored content.

Privacy, by construction rather than by promise

Every calculator runs entirely in your browser. Salary figures, loan balances, and debt amounts are processed on your own device and never transmitted to a server, because there is no server to transmit them to — the site is static files. This is a structural property rather than a policy commitment, which means it cannot quietly change. Details are in the privacy policy.

Corrections and contact

Corrections are genuinely wanted. If a figure here disagrees with an authoritative source, or a calculation looks wrong, write to contact@myloanmath.com — it will be investigated, and if it is an error it will appear on the corrections log with your correction credited if you would like it to be.