ChamTax (참택스)

chamtax.com — a free calculator for how much of a US Powerball / Mega Millions jackpot a winner actually keeps after tax.

Lottery headlines only ever show the announced jackpot. What you actually receive depends on US federal withholding (30% flat for non-resident aliens, or graduated up to 37% for US residents), the state the ticket was bought in, and — for non-US winners — their home country's own tax treatment of foreign lottery income. ChamTax runs all of that in one place.

• 21 countries/jurisdictions of residence supported, US included (all 50 states + DC)
• 26 languages
• Full Powerball draw history since 1992 and Mega Millions since 2002, cross-checked against official open data
• Dedicated guides for foreign nationals living in Korea (by nationality) and for Korean nationals living abroad

Other things in this repo

• press-kit.html — quick reference table for journalists/bloggers, plus an embeddable mini-calculator widget (widget-embed.html) anyone can drop into their own site with an <iframe>
• The per-country take-home data is also published as an open dataset (CC0): us-lottery-tax-data
• llms.txt — a structured summary for AI assistants/search tools citing this site

Stack

Static HTML/CSS/JS, no framework, deployed via GitHub Pages. package.json exists only to minify script.js/styles.css for production (npm run build:min) — not a build system in the usual sense. GitHub Actions handle IndexNow pings on content changes and daily lottery-archive backfills from official open data (see .github/workflows/).

This is not a lottery retailer or tax advisory service — figures are reference estimates, not tax advice.