Show HN: Convexly — a two‑minute quiz that tells you how bad you are at estimating

What it is

Convexly launched as a Show HN post and bills itself as a quick tool for founders to measure how well their confidence matches reality. Answer 10 questions in under two minutes, slide to indicate confidence, and get immediate metrics — Brier scores, calibration curves, an "upside ratio," and even dollar estimates of what your overconfidence might be costing you. The site promises feedback in seconds, not months.

How it works

You don't just pick true or false. The slider captures certainty — 75% means "I think this is true, but I'm not sure." After logging just a few decisions the product surfaces patterns: where you're overconfident, which categories you nail, and which bets have asymmetric upside. Think Good Judgment Project meets your VC spreadsheet. Resolve outcomes over time and watch your calibration score change; exportable reports and portfolio views are listed on the roadmap.

Why founders might care

Decision-making is emotional and expensive. How many times have you hired on gut and hoped for the best? Convexly puts a price tag on that gut. It has been reported that most founders are overconfident in the 70–90% range, and the app frames overconfidence as opportunity cost — not just an ego problem but a line item on a P&L. Want to stop playing it safe when the math says go big? This is the sort of nudge that could change how teams allocate risk.

Roadmap and business model

The basic quiz is free; upgrades add enterprise features and exports. It has been reported that Convexly is growing fast and plans Type 1/Type 2 certifications, SSO, audit logs, API access, and integrations that capture predictions from chats or browsers. Skeptical? Fair. The claims are straightforward and measurable — run the two‑minute test and see if the numbers embarrass you.

Sources: convexly.app, Hacker News