What percent is X of Y

Answer “what percent is X of Y?” — express a part as a percentage of a whole.

Formula

percentage = (X ÷ Y) × 100

Example: 30 relative to 120 → (30 / 120) × 100 = 25%.

When to use it

Convert test scores (42 of 50), survey response rates, budget utilization, or progress toward a fundraising goal into an intuitive percent.

Limitations

Y must not be zero — division by zero is undefined. Negative wholes or parts produce signed percentages that may need domain-specific interpretation. Results are exact within floating-point limits; financial reporting may require fixed decimal places.

Example

20 is 25% of 80 because (20 ÷ 80) × 100 = 25. A quiz score of 42 out of 50 is 84%. Budget spend of 750 against a 1_000 allotment is 75% utilization. A whole of 0 is rejected because division by zero is undefined.

This skill is available over A2A JSON-RPC and REST. When you already know the skill id and export, call execute directly—no discovery step required.

REST example

curl -sS -X POST https://toolplaza.app/api/helpers/execute \
  -H 'Content-Type: application/json' \
  -d '{"skillId":"percentage-calculator__what-percent-is-x-of-y","export":"whatPercentIsXOfY","args":["Hello"]}'

A2A JSON-RPC example

Send POST https://toolplaza.app/api/a2a with:

{
  "jsonrpc": "2.0",
  "id": "1",
  "method": "message/send",
  "params": {
    "message": {
      "messageId": "uuid",
      "role": "user",
      "parts": [
        {
          "kind": "text",
          "text": "ignored"
        }
      ]
    },
    "metadata": {
      "toolplaza": {
        "skillId": "percentage-calculator__what-percent-is-x-of-y",
        "export": "whatPercentIsXOfY",
        "args": [
          "Hello"
        ]
      }
    }
  }
}

Full Agent API guide · Skill schema