moneycrunchlab
financial calculators — no sign-up, no tracking, embeddable
MoneyCrunchLab is a collection of 25 free financial calculators covering mortgages, debt payoff, savings, and retirement. Every tool computes entirely in your browser — the numbers you type never leave it — with no sign-up, no tracking, and no ads inside the tools. Each calculator states its assumptions right next to the results and shows the losing side of a trade-off when there is one: the rent-vs-buy and 15-vs-30-year comparisons will happily tell you the "wrong" answer wins. The math is verified against closed-form financial formulas before publication, and every calculator can be embedded on any website with one line of HTML, free forever.
Features
25 interactive calculators: mortgages (recast, points, refinance break-even, amortization), debt (snowball vs avalanche, credit card minimums), savings, retirement/FIRE
100% client-side computation — your numbers never leave your browser
No sign-up, no tracking, no ads inside the tools
Assumptions stated next to every result
Math verified against closed-form financial formulas
Embeddable on any site with one line of HTML (free, attribution link included)
Static pages, system fonts, a few KB of vanilla JS each — instant load
Use Cases
See your real mortgage payoff date with extra payments or a lump sum
Compare debt snowball vs avalanche with your actual debts — payoff dates, total interest, verdict
Find out what minimum payments on a credit card really cost (and how long they take)
Decide rent vs buy over your true time horizon, with the down payment's opportunity cost included
Check how much house you can afford by the 28/36 rule lenders use
Compute your FIRE number with an adjustable withdrawal rate
Embed any calculator in your blog, class page, or client site — free
Comments
Hi Fazier 👋 I built MoneyCrunchLab after noticing that most financial calculators online are either ad-walled quiz funnels or worked examples with someone else's numbers. So I set myself three constraints and stuck to them: everything computes in your browser (the numbers you type never leave it — there's no backend to send them to), no sign-up and no tracking anywhere, and every calculator states its assumptions right next to the results. The comparison tools will even tell you when the "wrong" answer wins — the rent-vs-buy calculator has no problem telling you to keep renting. 25 calculators so far (mortgages, debt payoff, savings, retirement), each verified against closed-form financial formulas before publication. And every one of them embeds on any website with a single line of HTML, free forever — that part is for the bloggers and teachers here. If you find a number that looks wrong, tell me: I'll show the math or fix it within the day. That's the whole editorial policy. — Pierre-Antoine, indie maker at SilverBack Studio
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Comments
Hi Fazier 👋 I built MoneyCrunchLab after noticing that most financial calculators online are either ad-walled quiz funnels or worked examples with someone else's numbers. So I set myself three constraints and stuck to them: everything computes in your browser (the numbers you type never leave it — there's no backend to send them to), no sign-up and no tracking anywhere, and every calculator states its assumptions right next to the results. The comparison tools will even tell you when the "wrong" answer wins — the rent-vs-buy calculator has no problem telling you to keep renting. 25 calculators so far (mortgages, debt payoff, savings, retirement), each verified against closed-form financial formulas before publication. And every one of them embeds on any website with a single line of HTML, free forever — that part is for the bloggers and teachers here. If you find a number that looks wrong, tell me: I'll show the math or fix it within the day. That's the whole editorial policy. — Pierre-Antoine, indie maker at SilverBack Studio
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