• VALIDATED
  • ADJUSTED
  • REVIEW
  • LOGGED

How to automate invoice tax calculations with your AI

Connect this MCP to your AI client to handle math-heavy invoice adjustments. Your agent stops guessing percentages and starts using exact calculations.

Ask AI about this page

Short answer

How can I use AI to calculate invoice taxes and discounts?

Your AI uses deterministic math tools to apply specific VAT rates or discount amounts to your line items. This ensures the math is exact every time. You get a breakdown of how the agent handles these calculations below.

Where every calculation lands.

The outcomes of your math tasks.

Once your agent runs the math, the results land in these specific states.

VALIDATED

Exact tax totals

The AI calculates the precise VAT amount for each line item. You receive a clean list of tax-inclusive totals.

ADJUSTED

Applied discounts

The agent subtracts specific percentage discounts from your subtotal. You get the final price after the reduction.

REVIEW

Human verification

The AI flags any line items where the math looks unusual. You step in to confirm the final invoice before sending.

LOGGED

Audit trail

Every calculation is recorded as a discrete step. You can see exactly how the agent reached the final number.

The workflow

What your AI does when the invoice arrives.

The agent moves from reading your data to performing precise math operations.

  1. Identify rates

    Your agent reads the invoice data to find the base price and the applicable tax or discount percentage.

    calculate_percent_of

  2. Calculate tax

    The agent determines the exact tax amount based on the line item price.

    calculate_percent_of

  3. Apply discounts

    The agent calculates the price increase or decrease based on your specific discount rules.

    calculate_increase_by

  4. Finalize totals

    The agent sums the adjusted line items to produce a final invoice total.

    calculate_percent_ofcalculate_increase_by

Try it

Copy these to start.

Paste these prompts into your chat to begin.

Starting points

Swap the bracketed text for your actual data sources like a CSV or a specific invoice ID.

JavaScript Math Connector

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

Connector linkhttps://edge.vinkius.com/vk_preview_ttJ13k8D00YxXRgwTrEjCYGv4nA6JgPMQz340RM2/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 — JavaScript Math capabilities are ready to use.
Configuration · claude_desktop_config.jsonCopy
{
  "mcpServers": {
    "percentage-calculation-engine-mcp": {
      "url": "https://edge.vinkius.com/vk_preview_ttJ13k8D00YxXRgwTrEjCYGv4nA6JgPMQz340RM2/mcp"
    }
  }
}
Copy into chat04

  • Calculate a 15% VAT for every line item in my 'Q4_Invoices.csv' file.

  • Apply a 10% discount to the total amount in the 'Client_Alpha' invoice.

  • Use the Percentage Calculation Engine to find the tax amount for the items in my current spreadsheet.

  • Calculate a 5% service fee increase for all line items in the 'Vendor_List' document.

  • Claude
  • ChatGPT
  • Cursor
  • VS Code
  • Windsurf
  • Claude Code
  • JetBrains
  • Cline

Start here

Connect Percentage Calculation Engine once, then ask.

One click connects this MCP to your client. Your credentials stay encrypted, and you can find the full technical details on the Connector page.

Connect Percentage Calculation Engine to your AI

FAQ

How this task behaves.

  • 01

    Does the AI guess the tax percentage?

    No. The AI uses the specific math tools to calculate exact percentages provided in your prompt.

  • 02

    Can the AI change my original invoice files?

    No. The AI only performs calculations. It does not have the capability to write to or overwrite your original files.

  • 03

    Can it handle multiple different tax rates at once?

    Yes, as long as you provide the specific rate for each item in your instructions.

  • 04

    Will it automatically send the invoice to my client?

    No. The AI only calculates the numbers. You must handle the actual sending or filing of the invoice.

  • 05

    Does it work with any spreadsheet?

    It works with any data your AI client can read and pass to the math tools.

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

Connect JavaScript Math to Claude, Cursor, ChatGPT & more