The archive · Developer & Business Tools · Product decision · 2026
Calquio: an ex-coder's AI-built calculators drew a 314-point Show HN
An ex-coder used AI to rebuild finance calculators he hated; ~$100 of API spend produced 60+ tools and a 314-point Show HN.
Calquio
What the business is
Calquio is a free, multi-language (EN/DE/FR/JA) web site of 60+ calculators and finance explainers — compound interest, mortgage, loan amortization, savings goals, retirement, BMI, timezone, regex — built on Next.js with shadcn-style components.
Starting capital：~$100 in AI API costs over two weeks (Claude via Windsurf)
How it started
The founder (HN handle ivcatcher) studied coding but quit years earlier, convinced he was too slow and made too many bugs, and moved into investing as an associate at an early-stage angel fund. A self-described Buffett nerd who constantly runs compound-interest calculations, he found every online calculator ugly, ad-covered and inflexible about compounding frequency and year-by-year detail; when vibe coding took off, he decided to try building the calculator he wanted.
What happened
Over two weeks and roughly $100 in AI API costs (Claude via Windsurf, using the Opus 4.5 thinking model), the founder produced 60+ calculators — compound interest first, then mortgage, loan amortization, savings goals, retirement projections, then BMI, timezone and regex tools. The AI picked most of the stack (Next.js, React, TailwindCSS, shadcn/ui) when told to make it modern and clean, and the site shipped in four languages. The Show HN on 2026-01-19 drew 314 points and 433 comments and turned into a long argument about whether AI-generated apps count as real engineering: some commenters flagged the author as a bot, others noted the tools duplicated spreadsheets, and the founder answered that the site was a learning first step toward a product that could actually help people.
No ending yet — it is still running.
Background
Calquio is a free web site of finance and utility calculators plus explanatory articles, started by a former coder who had spent years away from programming working at an early-stage angel fund. The flagship page is a compound-interest calculator with compounding frequency, inflation adjustment and a year-by-year breakdown table — features its founder says every calculator he tried online lacked.
The bet is personal: that after quitting coding because of imposter syndrome, he could come back by describing products clearly and letting an AI do the typing, using domain knowledge (financial math, UX taste, architecture instincts) he had kept from years in investing. Two weeks and roughly $100 of API spend produced 60+ calculators in four languages (EN/DE/FR/JA), with the AI choosing most of the stack.
The Show HN on 2026-01-19 drew 314 points and 433 comments and became one of the day's biggest arguments about whether AI-assisted output is real software engineering — some called it a toy or a bot, others welcomed the founder back to building. The site stayed live afterward, and the founder described the calculators as a learning first step toward a product that uses his investing experience.
What has to be true
- The founder's own investing habits produced a specific, personally felt spec — compounding frequency, inflation toggles, year-by-year tables — that generic ad-supported calculators ignored.
- Two weeks and ~$100 of API spend made the entry barrier near zero, so the bet that AI could bring a lapsed coder back was cheap enough to actually run.
- Shipping 60+ tools and four languages showed the marginal cost of a new product under AI was tiny, which is the real economics of the bet.
- The 314-point, 433-comment thread proved the product was less the point than the phenomenon: HN spent months debating AI authorship and what counts as engineering.
What can be applied
A domain expert who stopped coding can ship again with AI, but the wedge must be real: fix a tool you personally use, keep scope small, and let one good page lead the rest.
Aftermath
As of 2026-09-05 calquio.com is still live with the compound-interest calculator, a blog, and related articles such as a fee-impact comparison; it remains a free, unmonetized solo project with no company or funding attached. The founder said in the launch thread that the calculators are a learning first step and that he hopes to apply years of investing experience to a future product that actually helps people.
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