{"uid":"cap_CSjtsOM6RFhAxuUvjC_Jh","slug":"jewelry-maker-calc-ring-size-converter-81fd4a25","name":"Jewelry Maker Calc – Ring Size Converter","description":"Convert a ring size between US, EU (ISO circumference), UK letter, inside diameter and circumference in mm and inches.","url":"https://jewelry-calc.x402tookit.com/ring-size?utm_source=zero.xyz","method":"GET","headers":{},"bodySchema":{"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"]},"mmPerFullUsSize":{"type":["null","number"]},"circumferenceInches":{"type":["null","number"]},"usSizeNearestQuarter":{"type":["null","number"]}}}}}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.02","displayCostAsset":"USDC","priceDynamic":false,"priceHint":null,"priceStatus":"priced","priceSource":"probe","requiresHandshake":false,"reviewCount":0,"rating":{"score":"0.00","successRate":"0.00","reviews":0,"stars":null,"state":"unrated"},"availabilityStatus":"unknown","priceObserved":null,"sessionDeposit":null,"pricing":{"kind":"static","summary":"$0.02/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.02","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_SUKg47bzoQfPHSEd3yLqK","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.02","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Converts a ring size among US, EU (ISO circumference), UK letter, inside diameter, and circumference in both mm and inches.","exampleAgentPrompt":"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?","exampleUseCases":[{"title":"Buying a ring from a European jeweler","prompt":"I wear a US size 6.5 ring and I need to order from a German jewelry site that uses EU sizes — what's my EU size and inside diameter in mm?"},{"title":"Converting a ring measured with a string","prompt":"I measured my finger circumference as 57mm — can you tell me what that is in US ring size, EU size, and UK letter?"},{"title":"Gift shopping with only UK size known","prompt":"My partner's ring box says size P UK — can you convert that to US and EU sizes so I can order from an American jeweler?"}],"resultDescription":"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.","failureModes":["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"],"whenToPreferThis":"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.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-10-29T13:13:42.168Z","isFirstParty":false,"canonicalSlug":"jewelry-maker-calc-ring-size-converter-81fd4a25"}