# Jewelry Maker Calc – Ring Size Converter

> Jewelry Maker Calc – Ring Size Converter is a paid API for AI agents from jewelry-calc.x402tookit.com, paid per call via x402, $0.02/call, status unknown (last checked 2026-10-29).

Converts a ring size among US, EU (ISO circumference), UK letter, inside diameter, and circumference in both mm and inches.

## Facts

- Endpoint: GET https://jewelry-calc.x402tookit.com/ring-size?utm_source=zero.xyz
- Price: $0.02/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-29
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/jewelry-maker-calc-ring-size-converter-81fd4a25
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_CSjtsOM6RFhAxuUvjC_Jh

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability jewelry-maker-calc-ring-size-converter-81fd4a25
```

Example prompt: I need to order a ring from a European jeweler — can you convert US ring size 7 to the equivalent EU size, UK letter, and inside diameter in mm?

## When to prefer this

Use this endpoint when you need to programmatically convert ring sizes across US, EU, UK, diameter, and circumference systems — especially when helping users shop internationally, manufacturing jewelry, or interpreting measurements from a physical ring. It is purpose-built for ring size conversion with full multi-system output in a single call, making it more efficient than generic unit converters or manual ring size charts.

## Known failure modes

- Missing required input: no query parameter provided — returns an error or empty/null result
- Out-of-range US size (below 0 or above 16) — may return null or an invalid result
- Non-numeric or malformed parameter value — request fails with a validation error
- Ambiguous input if multiple size parameters are provided simultaneously — only one should be used

## How this service works

Convert a ring size between US, EU (ISO circumference), UK letter, inside diameter and circumference in mm and inches.

## Output

Returns a comprehensive size object with the equivalent ring size in all major systems: US size (decimal and nearest quarter), EU/ISO size (circumference in mm), UK letter, inside diameter in mm and inches, inside circumference in mm and inches, and mm per full US size increment. Also includes a summary, disclaimer, and any degraded/partial result flags.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [],
     "properties": {
      "euSize": {
       "type": "number",
       "description": "EU / ISO size = inside circumference in mm"
      },
      "usSize": {
       "type": "number",
       "description": "US ring size, 0 to 16 (use exactly one input)"
      },
      "diameterMm": {
       "type": "number",
       "description": "Inside diameter in mm"
      },
      "circumferenceMm": {
       "type": "number",
       "description": "Inside circumference in mm"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object",
     "properties": {
      "asOf": {
       "type": [
        "null",
        "string"
       ]
      },
      "euSize": {
       "type": [
        "null",
        "number"
       ]
      },
      "source": {
       "type": [
        "null",
        "string"
       ]
      },
      "ukSize": {
       "type": [
        "null",
        "string"
       ]
      },
      "usSize": {
       "type": [
        "null",
        "number"
       ]
      },
      "reasons": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "summary": {
       "type": [
        "null",
        "string"
       ]
      },
      "verdict": {
       "type": [
        "null",
        "string"
       ]
      },
      "degraded": {
       "type": [
        "boolean",
        "null"
       ]
      },
      "diameterMm": {
       "type": [
        "null",
        "number"
       ]
      },
      "disclaimer": {
       "type": [
        "null",
        "string"
       ]
      },
      "notChecked": {
       "type": [
        "array",
        "null"
       ],
       "items": {
        "type": "string"
       }
      },
      "diameterInches": {
       "type": [
        "null",
        "number"
       ]
      },
      "circumferenceMm": {
       "type": [
        "null",
        "number"
       ]
      
… (truncated)
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/jewelry-maker-calc-ring-size-converter-81fd4a25/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from jewelry-calc.x402tookit.com](https://www.zero.xyz/host/jewelry-calc.x402tookit.com/llms.txt)