Jackpot Calculator

Official4 tools

by jiankn · JavaScript

Estimate US lottery taxes, compare cash and annuity, split pool prizes and calculate jackpot odds.

MCP Server: io.github.jiankn/jackpot-calculator

The io.github.jiankn/jackpot-calculator MCP server provides tools to estimate US lottery taxes, compare cash versus annuity outcomes, split pool prizes, and calculate jackpot odds. It is focused on computing and comparing lottery-related figures from common inputs.

🛠️ Key Features

Estimate US lottery taxes
Compare cash and annuity options
Split pool prizes
Calculate jackpot odds

🚀 Use Cases

Determine estimated tax impact for US lottery winnings
Compare payment structures (cash vs annuity)
Recalculate prize amounts when sharing a pool
Compute and review jackpot odds

⚡ Developer Benefits

Provides focused calculation capabilities for lottery scenarios
Supports multiple related computations in one server
Enables programmatic comparison of cash/annuity and pool splits

Captured live from the server via tools/list.

calculate_lottery_payout

Estimate taxes and withholding on a known lottery cash prize. Input dollars; result integer cents. Bundled 2026 rules.

Parameters6

prize	number	required	US dollars, not cents. Maximum $1 trillion.
game	string	optional
stateCode	string	required	US residence and ticket-purchase state, two-letter code. Cross-state claims are not modeled.
locality	string	optional	Only valid with stateCode NY.
status	string	optional
otherIncome	number	optional	Other annual income in US dollars before the standard deduction.

Raw schema

{
  "type": "object",
  "properties": {
    "prize": {
      "type": "number",
      "exclusiveMinimum": 0,
      "maximum": 1000000000000,
      "description": "US dollars, not cents. Maximum $1 trillion."
    },
    "game": {
      "default": "custom",
      "type": "string",
      "enum": [
        "powerball",
        "megaMillions",
        "custom"
      ]
    },
    "stateCode": {
      "type": "string",
      "enum": [
        "AK",
        "AL",
        "AR",
        "AZ",
        "CA",
        "CO",
        "CT",
        "DC",
        "DE",
        "FL",
        "GA",
        "HI",
        "IA",
        "ID",
        "IL",
        "IN",
        "KS",
        "KY",
        "LA",
        "MA",
        "MD",
        "ME",
        "MI",
        "MN",
        "MO",
        "MS",
        "MT",
        "NC",
        "ND",
        "NE",
        "NH",
        "NJ",
        "NM",
        "NV",
        "NY",
        "OH",
        "OK",
        "OR",
        "PA",
        "RI",
        "SC",
        "SD",
        "TN",
        "TX",
        "UT",
        "VA",
        "VT",
        "WA",
        "WI",
        "WV",
        "WY"
      ],
      "description": "US residence and ticket-purchase state, two-letter code. Cross-state claims are not modeled."
    },
    "locality": {
      "description": "Only valid with stateCode NY.",
      "type": "string",
      "enum": [
        "NYC",
        "YONKERS"
      ]
    },
    "status": {
      "default": "single",
      "type": "string",
      "enum": [
        "single",
        "joint",
        "headOfHousehold"
      ]
    },
    "otherIncome": {
      "default": 0,
      "description": "Other annual income in US dollars before the standard deduction.",
      "type": "number",
      "minimum": 0,
      "maximum": 1000000000000
    }
  },
  "required": [
    "prize",
    "stateCode"
  ],
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "additionalProperties": false
}

compare_lump_sum_annuity

Compare a published cash option with 30 growing annuity payments after taxes, including present value and break-even rate.

Parameters10

jackpot	number	required	Advertised annuity total in US dollars.
cashValue	number	required	Published cash option in US dollars; do not infer it from a fixed ratio.
game	string	optional
stateCode	string	required	US residence and ticket-purchase state, two-letter code. Cross-state claims are not modeled.
locality	string	optional	Only valid with stateCode NY.
status	string	optional
otherIncome	number	optional	Other annual income in US dollars before the standard deduction.
discountRate	number	optional	Annual discount rate as a fraction, e.g. 0.04 for 4%.
winners	integer	optional	Number of jackpot-winning tickets sharing the prize.
sharePercent	number	optional	Your percentage of one winning ticket.

Raw schema

{
  "type": "object",
  "properties": {
    "jackpot": {
      "type": "number",
      "exclusiveMinimum": 0,
      "maximum": 1000000000000,
      "description": "Advertised annuity total in US dollars."
    },
    "cashValue": {
      "type": "number",
      "exclusiveMinimum": 0,
      "maximum": 1000000000000,
      "description": "Published cash option in US dollars; do not infer it from a fixed ratio."
    },
    "game": {
      "default": "custom",
      "type": "string",
      "enum": [
        "powerball",
        "megaMillions",
        "custom"
      ]
    },
    "stateCode": {
      "type": "string",
      "enum": [
        "AK",
        "AL",
        "AR",
        "AZ",
        "CA",
        "CO",
        "CT",
        "DC",
        "DE",
        "FL",
        "GA",
        "HI",
        "IA",
        "ID",
        "IL",
        "IN",
        "KS",
        "KY",
        "LA",
        "MA",
        "MD",
        "ME",
        "MI",
        "MN",
        "MO",
        "MS",
        "MT",
        "NC",
        "ND",
        "NE",
        "NH",
        "NJ",
        "NM",
        "NV",
        "NY",
        "OH",
        "OK",
        "OR",
        "PA",
        "RI",
        "SC",
        "SD",
        "TN",
        "TX",
        "UT",
        "VA",
        "VT",
        "WA",
        "WI",
        "WV",
        "WY"
      ],
      "description": "US residence and ticket-purchase state, two-letter code. Cross-state claims are not modeled."
    },
    "locality": {
      "description": "Only valid with stateCode NY.",
      "type": "string",
      "enum": [
        "NYC",
        "YONKERS"
      ]
    },
    "status": {
      "default": "single",
      "type": "string",
      "enum": [
        "single",
        "joint",
        "headOfHousehold"
      ]
    },
    "otherIncome": {
      "default": 0,
      "description": "Other annual income in US dollars before the standard deduction.",
      "type": "number",
      "minimum": 0,
      "maximum": 1000000000000
    },
    "discountRate": {
      "default": 0.04,
      "description": "Annual discount rate as a fraction, e.g. 0.04 for 4%.",
      "type": "number",
      "minimum": 0,
      "maximum": 1
    },
    "winners": {
      "default": 1,
      "description": "Number of jackpot-winning tickets sharing the prize.",
      "type": "integer",
      "minimum": 1,
      "maximum": 10000
    },
    "sharePercent": {
      "default": 100,
      "description": "Your percentage of one winning ticket.",
      "type": "number",
      "exclusiveMinimum": 0,
      "maximum": 100
    }
  },
  "required": [
    "jackpot",
    "cashValue",
    "stateCode"
  ],
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "additionalProperties": false
}

calculate_pool_share

Estimate one equal member’s cash prize, taxes and withholding. Each member is assumed to have the specified tax profile.

Parameters7

prize	number	required	Whole ticket cash prize in US dollars.
members	integer	required	Equal owners of one ticket. Result assumes every member has the specified tax profile.
game	string	optional
stateCode	string	required	US residence and ticket-purchase state, two-letter code. Cross-state claims are not modeled.
locality	string	optional	Only valid with stateCode NY.
status	string	optional
otherIncome	number	optional	Other annual income in US dollars before the standard deduction.

Raw schema

{
  "type": "object",
  "properties": {
    "prize": {
      "type": "number",
      "exclusiveMinimum": 0,
      "maximum": 1000000000000,
      "description": "Whole ticket cash prize in US dollars."
    },
    "members": {
      "type": "integer",
      "minimum": 2,
      "maximum": 10000,
      "description": "Equal owners of one ticket. Result assumes every member has the specified tax profile."
    },
    "game": {
      "default": "custom",
      "type": "string",
      "enum": [
        "powerball",
        "megaMillions",
        "custom"
      ]
    },
    "stateCode": {
      "type": "string",
      "enum": [
        "AK",
        "AL",
        "AR",
        "AZ",
        "CA",
        "CO",
        "CT",
        "DC",
        "DE",
        "FL",
        "GA",
        "HI",
        "IA",
        "ID",
        "IL",
        "IN",
        "KS",
        "KY",
        "LA",
        "MA",
        "MD",
        "ME",
        "MI",
        "MN",
        "MO",
        "MS",
        "MT",
        "NC",
        "ND",
        "NE",
        "NH",
        "NJ",
        "NM",
        "NV",
        "NY",
        "OH",
        "OK",
        "OR",
        "PA",
        "RI",
        "SC",
        "SD",
        "TN",
        "TX",
        "UT",
        "VA",
        "VT",
        "WA",
        "WI",
        "WV",
        "WY"
      ],
      "description": "US residence and ticket-purchase state, two-letter code. Cross-state claims are not modeled."
    },
    "locality": {
      "description": "Only valid with stateCode NY.",
      "type": "string",
      "enum": [
        "NYC",
        "YONKERS"
      ]
    },
    "status": {
      "default": "single",
      "type": "string",
      "enum": [
        "single",
        "joint",
        "headOfHousehold"
      ]
    },
    "otherIncome": {
      "default": 0,
      "description": "Other annual income in US dollars before the standard deduction.",
      "type": "number",
      "minimum": 0,
      "maximum": 1000000000000
    }
  },
  "required": [
    "prize",
    "members",
    "stateCode"
  ],
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "additionalProperties": false
}

calculate_lottery_odds

Calculate jackpot coverage for distinct combinations in one drawing and optional before-tax expected ticket return.

Parameters3

game	string	required
tickets	integer	optional	Different number combinations in the SAME drawing; repeated combinations do not add coverage.
jackpotCash	number	optional	Optional jackpot cash option in US dollars, required to compute expected ticket return.

Raw schema

{
  "type": "object",
  "properties": {
    "game": {
      "type": "string",
      "enum": [
        "powerball",
        "megaMillions"
      ]
    },
    "tickets": {
      "default": 1,
      "description": "Different number combinations in the SAME drawing; repeated combinations do not add coverage.",
      "type": "integer",
      "minimum": 1,
      "maximum": 302575350
    },
    "jackpotCash": {
      "description": "Optional jackpot cash option in US dollars, required to compute expected ticket return.",
      "type": "number",
      "exclusiveMinimum": 0,
      "maximum": 1000000000000
    }
  },
  "required": [
    "game"
  ],
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "additionalProperties": false
}

README.md5 KBView on GitHub

Jackpot Calculator MCP

Four read-only MCP tools for US lottery prize taxes, cash vs annuity comparisons, equal pool shares and jackpot probabilities. Calculations use a fixed 2026 data snapshot and the same engine as Jackpot Calculator.

Connect to the hosted server

Add this Streamable HTTP URL in a client that supports remote MCP servers:

text

https://jackpot-calculator-mcp.jiankn.workers.dev/mcp

No API key is required. The public endpoint allows up to 120 requests per minute per IP at the Cloudflare edge; rate limiting is approximate, not a global quota. Connection examples and output units: Jackpot Calculator MCP setup.

Tools

Tool	Required inputs	Output
`calculate_lottery_payout`	`prize`, `stateCode`	Estimated final tax, withholding and cash take-home
`compare_lump_sum_annuity`	`jackpot`, `cashValue`, `stateCode`	Cash and 30-payment annuity, discounted present value and break-even rate
`calculate_pool_share`	`prize`, `members`, `stateCode`	One equal owner's share with the whole-ticket withholding threshold
`calculate_lottery_odds`	`game`	Distinct-combination jackpot probability; optional expected return with `jackpotCash`

Money inputs are US dollars. Tax/payout results use integer cents. The odds tool reports money in dollars. Rates and probabilities are fractions, so 0.04 is 4%. Each result states its units, assumptions and related calculator.

Example tool call:

json

{
  "name": "calculate_lottery_payout",
  "arguments": { "prize": 1000000, "stateCode": "TX", "status": "single" }
}

The bundled 2026 calculation returns an estimated $320,000 final federal tax and $680,000 take-home, separately from $240,000 federal withholding. See the interactive lottery tax calculator to explore other states and filing statuses.

For game-specific cash estimates, select game: "powerball" or game: "megaMillions", provide the known cash prize and compare it with the Powerball payout calculator or Mega Millions tax calculator. For annuities provide both the published cash option and advertised annuity total; the package never guesses the cash option from a fixed percentage.

Run locally from the source or release archive

Node.js 22.12 or newer is required.

git clone https://github.com/jiankn/jackpot-calculator-mcp.git
cd jackpot-calculator-mcp
npm ci
npm test
node src/cli.mjs

The last command starts an MCP stdio server and waits for a client; it is not an interactive CLI prompt. Configure a stdio client with command: "node" and args: ["/absolute/path/to/jackpot-calculator-mcp/src/cli.mjs"]. Only protocol messages go to stdout.

Release archives can also be installed with npm install ./jackpot-calculator-mcp-0.1.0.tgz. An npm registry listing is optional and is not needed for the hosted endpoint.

Calculation boundaries

US resident taxpayers, same residence and ticket-purchase state; cross-state credits and nonresident alien withholding are not modeled.
Federal and state tax data is bundled, with original source URLs and dates. No live jackpot lookup, automatic tax update, ticket purchase or ticket check.
Standard deduction and incremental income tax. State head-of-household uses single-filer state brackets. California assumes a California Lottery prize.
NYC and Yonkers need an explicit locality with stateCode: "NY". Maryland uses an average county rate; other local income taxes are excluded.
Annuities use 30 payments, first immediately and then annual payments growing 5%. Tax rules and other income stay constant. Future tax law and investment taxes are not modeled. Annuity methodology and calculator.
Pool outputs assume all members have the same tax profile. Different people need separate scenarios. Individually rounded fractional-cent shares can differ slightly from the whole prize.
Odds assume distinct combinations in one drawing. Expected value excludes taxes, Power Play, jackpot sharing and California pari-mutuel payout differences.

Estimates only, not tax or financial advice. Independent of Powerball, Mega Millions, the Multi-State Lottery Association and state lottery operators. Sources and methodology.

Development and releases

npm test checks known payouts, validation, pool withholding, annuity totals, odds and real stdio/HTTP protocol calls. npm run verify:package packs the allowlisted files, installs the archive into a clean directory and invokes the installed server. CI runs both on Windows and Linux.

scripts/sync-engine.mjs is a maintainer-only snapshot step run within the website checkout, before release. It records source hashes in PROVENANCE.md. Standalone users already have the copied files and do not need to run it.

Code: MIT. Compiled data: CC BY 4.0; see LICENSE-DATA.md and the source URLs inside data/. Issues: https://github.com/jiankn/jackpot-calculator-mcp/issues

Install

Tools (4)

calculate_lottery_payoutcompare_lump_sum_annuitycalculate_pool_sharecalculate_lottery_odds

Remote endpoint

Streamable HTTP

Hosted server - connect over the network, no local install.

url

https://jackpot-calculator-mcp.jiankn.workers.dev/mcp

Add to VS Code Add to Cursor

claude_desktop_config.json

json

{
  "mcpServers": {
    "jackpot-calculator": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-remote",
        "https://jackpot-calculator-mcp.jiankn.workers.dev/mcp"
      ]
    }
  }
}

Desktop config is stdio-only; this bridges via mcp-remote. Native remote: Settings > Connectors.

MCP Server: io.github.jiankn/jackpot-calculator

🛠️ Key Features

🚀 Use Cases

⚡ Developer Benefits

calculate_lottery_payout

compare_lump_sum_annuity

calculate_pool_share

calculate_lottery_odds

Jackpot Calculator MCP

Connect to the hosted server

Tools

Run locally from the source or release archive

Calculation boundaries

Development and releases

Install

Remote endpoint

Related servers