Percentage change

Measure percentage change between an initial value and a final value — the standard growth or decline rate.

Formula

change % = ((final − initial) ÷ initial) × 100

Positive results indicate increase; negative results indicate decrease. Example: from 80 to 100 → +25%; from 200 to 150 → −25%.

When to use it

Report revenue deltas, stock price moves, weight-tracking trends, or year-over-year KPIs in dashboards and slide decks.

Limitations

Initial value cannot be zero — percent change from zero is undefined. Very small denominators inflate percentages dramatically. The formula is symmetric in math but not in perception (a 50% drop requires a 100% gain to recover).

Example

Going from 80 to 100 is a +25% change because ((100 − 80) ÷ 80) × 100 = 25. Going from 200 to 150 is −25%. A revenue jump from 1_000 to 1_150 is +15%, while an initial value of 0 is rejected because percent change from 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__percent-change","export":"percentageChange","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__percent-change",
        "export": "percentageChange",
        "args": [
          "Hello"
        ]
      }
    }
  }
}

Full Agent API guide · Skill schema