• ACCURACY
  • TAXES
  • LOGISTICS
  • REVIEW

How to calculate shopping cart totals with your AI

Connect this MCP to your AI client to handle precise math. It handles the heavy lifting for every transaction.

Ask AI about this page

Short answer

How do I get my AI to calculate accurate cart totals?

Your AI uses the calculate_currency tool to perform integer arithmetic on all line items, shipping fees, and tax rates. This prevents the rounding errors common in standard LLM math. You'll get exact totals every time.

The results of precise math

Where the math lands.

Once connected, your AI handles these specific financial tasks.

ACCURACY

Penny-perfect totals

The AI uses integer math to sum every item in a cart. You get totals that match your actual ledger.

TAXES

Correct tax application

The agent applies tax rates to subtotal amounts. It ensures the final sum accounts for every cent of tax owed.

LOGISTICS

Shipping fee inclusion

Shipping costs are added to the product sum. The AI treats shipping as a distinct integer value for the final calculation.

REVIEW

Human verification

The AI presents the breakdown of the math. You check the logic before finalizing any transaction or invoice.

The workflow

What your AI does when the data arrives.

The AI doesn't guess the math. It uses a dedicated tool to ensure the numbers are right.

  1. Gather items

    The AI pulls the individual prices and quantities from your provided list or database.

    calculate_currency

  2. Apply taxes

    It calculates the tax amount based on the specific rate you provide.

    calculate_currency

  3. Add shipping

    The agent adds the shipping cost to the subtotal and tax amounts.

    calculate_currency

  4. Finalize sum

    The tool produces a single, accurate integer representing the total cost.

    calculate_currency

Try it

Copy these to start.

Use these prompts to trigger the math engine.

Starting points

Swap the bracketed info for your actual data like your spreadsheet or order list.

currency.js Connector

You're all set. Choose your MCP client and follow the setup instructions.

Connector linkhttps://edge.vinkius.com/vk_preview_5NKbd1XQQAcf3ixbQFgDqA1EW0unjlSmIiGFqbYs/mcp

Claude Desktop

Follow the steps below to connect in seconds.

  1. 1In Claude Desktop, open Settings → Connectors.
  2. 2Click “Add custom connector” and paste the connector link above as the remote MCP server URL.
  3. 3Click Add and start a new chat — currency.js capabilities are ready to use.
Configuration · claude_desktop_config.jsonCopy
{
  "mcpServers": {
    "currency-math-engine-mcp": {
      "url": "https://edge.vinkius.com/vk_preview_5NKbd1XQQAcf3ixbQFgDqA1EW0unjlSmIiGFqbYs/mcp"
    }
  }
}
Copy into chat04

  • Calculate the total for this list of products from my Google Sheet: [link]

  • Sum these items including a 7% sales tax and $15 shipping: [list]

  • Check the math on this order from my Shopify store: [order details]

  • Add up the items in this JSON object and include the shipping fee: [json data]

  • Claude
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Start here

Connect Currency Math Engine once, then ask.

Click the link to connect the MCP to your client. Your credentials stay encrypted and the setup is instant.

Connect Currency Math Engine to your AI

FAQ

How this task behaves

  • 01

    Does the AI use floating-point math?

    No. It uses integer arithmetic to avoid the rounding errors that happen with decimals.

  • 02

    Can the AI change my actual prices in my database?

    No. The AI only reads the data you provide to perform calculations. It cannot write or edit your source files.

  • 03

    Can it handle different currencies?

    It calculates based on the integer values you provide. You must ensure the input is in a single consistent currency.

  • 04

    Will it automatically send invoices?

    No. The AI calculates the totals, but you must manually trigger any sending or billing actions.

  • 05

    How does it handle tax rates?

    You provide the tax rate, and the AI uses the tool to calculate the exact amount to add to the total.

  • More questions about Currency Math Engine? The Connector page answers them. See everything the Currency Math Engine Connector can do

Connect currency.js to Claude, Cursor, ChatGPT & more