Circle Calculator
Open Circle Calculator on Happytails.ai. This view has the same page content and links, with explicit tool capabilities. Read the processing notes before using a tool.
Tool capabilities
{
"id": "circle",
"category": "calculators",
"built": true,
"requirements": "Radius/diameter/circumference/area modes with consistent units.",
"implementation": {
"fields": [
{
"key": "r",
"label": "Radius",
"value": 5,
"type": "number"
}
],
"input": false,
"note": "",
"live": true,
"presentation": "metrics",
"experience": {
"automatic": true,
"single": false,
"inputMaxLength": 1000000,
"inputMode": "text",
"label": "Your text",
"placeholder": "Type or paste your input…",
"help": "Change the input or settings to update your result. Results update as you type. Up to 1,000,000 characters.",
"helpParts": [
"Change the input or settings to update your result.",
"Results update as you type.",
"Up to 1,000,000 characters."
],
"action": null
},
"mode": "automatic",
"interactive": false
},
"execution": "POST /api/v1/tools/circle/run",
"api": {
"id": "circle",
"name": "Circle",
"category": "calculators",
"description": "Calculate a circle’s diameter, circumference, and area from its radius.",
"notes": "",
"human_path": "/en/calculators/circle/",
"method": "POST",
"endpoint": "/api/v1/tools/circle/run",
"schema_url": "/api/v1/tools/circle",
"input_schema": {
"type": "object",
"additionalProperties": false,
"properties": {
"input": {
"type": "string",
"maxLength": 1000000,
"default": "",
"description": "Plain text input. File tools use files instead unless otherwise documented."
},
"options": {
"type": "object",
"additionalProperties": false,
"properties": {
"r": {
"type": "number",
"description": "Radius",
"default": 5.0
}
}
}
}
},
"output_schema": {
"type": "object",
"required": [
"tool",
"result"
],
"properties": {
"tool": {
"type": "string"
},
"result": {
"type": "object",
"required": [
"text",
"files"
],
"properties": {
"text": {
"type": [
"string",
"null"
]
},
"data": {
"description": "Parsed JSON when the textual result is JSON."
},
"name": {
"type": "string"
},
"mime": {
"type": "string"
},
"files": {
"type": "array",
"items": {
"type": "object",
"required": [
"name",
"mime",
"bytes",
"base64"
],
"properties": {
"name": {
"type": "string"
},
"mime": {
"type": "string"
},
"bytes": {
"type": "integer"
},
"base64": {
"type": "string",
"contentEncoding": "base64"
}
}
}
}
}
}
}
},
"processing": "Server; same transformation code as browser tools",
"limits": {
"request_bytes": 8388608,
"input_characters": 1000000,
"files_bytes": 5242880,
"max_files": 0,
"timeout_seconds": 12
}
},
"agent_processing": "Server; same transformation code as browser tools",
"browser_agent": {
"supported": true,
"name": "run_current_tool",
"discovery": "WebMCP on the human page in a supporting browser",
"verification": "See audit/API-AUDIT.md; availability is not verification"
}
}Page guide
Calculate a circle’s diameter, circumference, and area from its radius.
How to use Circle
- Enter the values you want to calculate and choose the relevant units or settings.
- The result updates as you type. Adjust the available settings if needed.
- Review the result, then use Copy result or a download link when available.
What to expect
Calculate a circle’s diameter, circumference, and area from its radius. Use one consistent length unit. Circumference is 2πr and area is πr². Area uses the square of your chosen unit.