The Jackpot Calculator MCP server gives compatible AI clients four read-only tools: lottery prize tax estimates, cash versus annuity comparisons, equal lottery pool shares and jackpot probabilities. It uses the same calculation engine as the lottery tax calculator on this website. The first release, 0.1.0, uses a fixed 2026 tax snapshot with source URLs and verification dates.
Connect your AI client
In a client that supports remote Model Context Protocol servers, add a server with the Streamable HTTP transport and this URL:
https://jackpot-calculator-mcp.jiankn.workers.dev/mcpNo API key or account is needed. Once connected, the client can discover the four tools below. The public service allows approximately 120 requests per minute per IP at the Cloudflare edge. It calculates the numbers you supply; it does not fetch current jackpots.
Available tools
| Tool | Required inputs | Result |
|---|---|---|
calculate_lottery_payout | prize, stateCode | Cash take-home, final taxes and withholding |
compare_lump_sum_annuity | jackpot, cashValue, stateCode | 30 payments, tax estimates, present value and break-even rate |
calculate_pool_share | prize, members, stateCode | One equal member's share and estimated taxes |
calculate_lottery_odds | game | Jackpot probability; optional expected return with jackpotCash |
Tax tools accept two-letter state codes, single, joint or headOfHousehold filing status, and optional otherIncome. Use locality: "NYC" or "YONKERS" with stateCode: "NY" for those cities. The odds tool supports powerball and megaMillions.
Example: a $1 million Texas prize
Ask your connected client: “Estimate the tax on a $1 million lottery cash prize for a single Texas resident with no other income.” It can call:
{
"name": "calculate_lottery_payout",
"arguments": {
"prize": 1000000,
"stateCode": "TX",
"status": "single"
}
}Under the bundled 2026 rules, estimated final federal tax is $320,000, leaving $680,000. Federal withholding at claim is $240,000, which leaves about $80,000 more federal tax due at filing. The tool returns those amounts separately.
Input and output units
Enter money in US dollars: 1000000 means $1 million. Payout, annuity and pool results use integer cents: 68000000 means $680,000. The odds tool's money results use dollars. Rates and probabilities use fractions, so a discountRate of 0.04 means 4%. Every result labels its units.
For an annuity, supply both the advertised jackpot and its published cash option. They are separate amounts; the server does not infer one from a fixed ratio. The Powerball calculator and Mega Millions calculator show the website's current dated estimates. The MCP package itself does not contain live jackpot data.
Sources and assumptions
Calculations assume a US resident who lives in the state where the ticket was bought, uses the standard deduction and pays incremental income tax. Cross-state tax credits and nonresident alien withholding are excluded. State head-of-household estimates use single-filer state brackets. California's exemption assumes a California Lottery prize. Maryland uses an average county rate; local taxes outside NYC, Yonkers and that Maryland average are excluded.
Annuities have 30 payments: the first immediately, followed by 29 annual payments increasing by 5%. The model holds tax rules and other income constant for every payment; it does not predict future tax law or investment taxes. Compare the schedule in the lottery annuity calculator.
Pool results assume each equal member has the specified tax profile. Run separate scenarios when members' incomes or filing statuses differ. The lottery pool calculator explains group ownership and claims. Odds assume different number combinations in the same drawing; repeated combinations do not add coverage. Expected return is before tax and excludes jackpot sharing, Power Play and California pari-mutuel differences. See lottery odds and expected value.
Result metadata includes sources, the calculation year and a related calculator link. Original sources and known limitations are in our methodology. These are estimates, not tax or financial advice.
Source code and local use
The public MCP source repository includes the stdio server, calculation snapshot, examples and tests. Node.js 22.12 or newer is required for local use. Clone it, run npm ci, and configure your stdio client to start node /absolute/path/to/jackpot-calculator-mcp/src/cli.mjs. The process waits for MCP requests and writes only protocol messages to stdout.
The code is MIT licensed; the compiled data is CC BY 4.0 with source attribution. The hosted service does not store calculation inputs or results in an application database. Cloudflare processes requests and operational request metadata; your AI client's own data policy also applies.