Finance In Your Pocket is a set of 39free financial calculators for people in the United States, built to answer specific questions rather than general ones. Not “how should I think about retirement” but “if I contribute $500 a month for twenty-two more years, where does that land” — a number, with the assumptions behind it visible.
Alongside the calculators there are 54 explainers and 8 published reference tables. Everything runs in your browser, nothing you type is transmitted or stored anywhere, and there is no account to create.
Why this exists
Financial calculators are one of the most duplicated things on the web, and most of them share the same three problems. They give you a number with no explanation of how it was produced. They use figures that were correct in some unnamed past year. And they tell you nothing about who built them or what they left out.
The premise here is that the parts everyone skips are the parts that matter. A mortgage payment is easy arithmetic; what is hard is knowing that the number excludes property tax variation between counties, that the rate you were shown is a survey average from a specific week, and that the affordability guideline it applies is a 1970s underwriting convention rather than a law of nature. Each calculator here says what it assumes and what it does not cover, next to the result.
Who maintains it
The site is built and maintained by Víctor Gil Vázquez. I am a web developer who builds and runs content sites; I am not a CPA, an enrolled agent, or a licensed financial adviser, and this site never claims otherwise. What I bring is the willingness to read the actual IRS notice rather than a summary of a summary, to write down where every number came from, and to publish the gaps instead of filling them with something plausible.
That is deliberately a modest claim. It is also why the editorial standards are written down and public: in a subject where being wrong has real consequences, the process should be checkable, not taken on trust because of a credential in a byline.
Corrections, questions, and requests for new calculators all go to the same place — the contact page. Reports of an incorrect figure get priority over everything else.
How the calculators work
Every calculator runs entirely in your browser. The numbers you enter are never sent to a server, never logged, and never stored anywhere outside your own device. There is no sign-up, no email capture, and no gate in front of a result.
Each calculator is built from a separate, pure calculation engine — a self-contained piece of code that takes inputs and returns results with no interface logic in it. Those engines are covered by an automated test suite that runs before every deployment, including tests written specifically for edge cases: zero and negative inputs, bracket boundaries, the exact income where a phase-out begins, the last month of an amortization schedule.
The formulas are not hidden. Where a calculation is not obvious, the page explains what it does in plain language, and the methodology page covers what each engine models, what it deliberately simplifies, and which regulatory dataset it reads from.
Where the data comes from
Any figure set by law or regulation — federal tax brackets, the standard deduction, the Social Security wage base, contribution limits, state rates — lives in its own constants file that records the source it came from and the date it was last verified against that source.
Primary sources come first: the IRS, the Social Security Administration, the CFPB, the Federal Reserve, the Census Bureau, HUD. Where a primary document is not machine-readable or not yet published, a reputable secondary source that transcribes it is used and named. Where neither exists, the figure is not published at all.
Those tables are readable at /reference — the same data the calculators use, with its sources and verification dates, so you can check the inputs rather than only seeing the output.
What this site is not
It is not financial advice, and the distinction is not a legal formality. Advice means telling a specific person what to do given their full circumstances. Everything here is educational: it explains how a rule or a calculation works and lets you apply it to your own numbers.
It is not a substitute for a professional. Anything involving an entity choice, a multi-state tax question, an inherited retirement account, or a decision where being wrong is expensive deserves a CPA or a fiduciary adviser. Several articles here say so explicitly at the point where the question gets past what a calculator can honestly answer.
And it is not exhaustive. Every calculator simplifies, because one that did not would be unusable. The Terms of Service state the limits formally; the notice beside each result states them where you will actually read them.
How the site is funded
Finance In Your Pocket is free and supported by advertising served through Google AdSense. There is no paywall, no premium tier, and no email list.
You can turn off ad personalization from the footer of any page, and the site honors the Global Privacy Control signal automatically for browsers that send it. Doing either does not take the ads away — it stops them being chosen from your activity on other sites, so what you see is drawn from the page in front of you instead. Readers in Europe and the UK are asked first, through Google's certified consent platform.
Advertising has no influence on content: advertisers have no input into what is written, nothing is recommended in exchange for payment, and there are no affiliate arrangements steering any comparison toward a particular lender or provider. A calculator returns identical results for every visitor regardless of their ad and privacy choices.
For details on what data advertising partners collect and how to control personalization, see the Cookie Policy, and the Privacy Policy for your rights over that data, including the CCPA/CPRA rights available to California residents.
Where it is going
The current priority is depth over breadth: making the existing calculators more complete and better documented, and publishing more of the underlying reference data, rather than adding tools faster than they can be maintained. A calculator nobody updates when the law changes is worse than no calculator, because it looks current.
If there is something you keep having to work out in a spreadsheet, that is exactly the kind of suggestion worth sending. Several of the tools here started that way.