{"uid":"cap_cDt-pF1m3CDSzq1-VMJU0","slug":"julian-day-number-to-gregorian-date-converter-2750fdb8","name":"Julian Day Number to Gregorian Date Converter","description":"Convert a Julian Day Number back to a proleptic-Gregorian date, with the ISO weekday (1=Monday..7=Sunday) and its name.","url":"https://datetime.openverbs.com/v1/from-jdn","method":"POST","headers":{},"bodySchema":{"type":"object","$schema":"https://json-schema.org/draft/2020-12/schema","required":["input"],"properties":{"input":{"type":"object","required":["type","method","bodyType","body"],"properties":{"body":{"type":"object","required":["jdn"],"properties":{"jdn":{"type":"integer","description":"Julian Day Number."}},"additionalProperties":false},"type":{"type":"string","const":"http"},"method":{"enum":["POST"],"type":"string"},"bodyType":{"enum":["json","form-data","text"],"type":"string"}},"additionalProperties":false}}},"responseSchema":null,"example":null,"exampleRequest":null,"tags":["x402"],"displayCostAmount":"0.004","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":"$0.004/call","primary":{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.004","per":"call","confidence":"exact"},"accepted":[{"kind":"static","protocol":"x402","network":"base","amountUsd":"0.004","per":"call","confidence":"exact"}]},"paymentMethods":[{"uid":"pm_bToIYUm29fs5b30-v7iid","protocol":"x402","methodType":"crypto","chain":"base","mode":"charge","costAmount":"0.004","costPer":"request","priority":0,"asset":"0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913","unit":"request","depositMicros":null,"planRef":null}],"brandName":null,"brandSlug":null,"brandBaseUrl":null,"brandDocsUrl":null,"whatItDoes":"Converts a Julian Day Number (JDN) to its proleptic-Gregorian calendar date, ISO weekday number (1=Monday..7=Sunday), and weekday name.","exampleAgentPrompt":"What Gregorian calendar date and day of the week does Julian Day Number 2451545 correspond to?","exampleUseCases":[{"title":"Decoding astronomical JDN timestamps","prompt":"I have an astronomical dataset that records events by Julian Day Number — can you convert JDN 2460310 to its Gregorian date and tell me what day of the week it falls on?"},{"title":"Historical date reconstruction from JDN","prompt":"I found a Julian Day Number 2299161 in an old historical record. What is the corresponding proleptic-Gregorian date and weekday?"},{"title":"Calendar system interoperability in software","prompt":"My application stores timestamps as Julian Day Numbers internally. Convert JDN 2440588 to its Gregorian date and ISO weekday so I can display it to users correctly."}],"resultDescription":"Returns the proleptic-Gregorian calendar date (year, month, day) corresponding to the given Julian Day Number, along with the ISO weekday number (1=Monday through 7=Sunday) and the full weekday name (e.g. 'Wednesday').","failureModes":["Missing required 'jdn' field returns a validation error","Non-integer or float value for jdn may be rejected","Extremely large or negative JDN values outside supported range may return an error","Malformed request body returns a 400-level error"],"whenToPreferThis":"Use this endpoint when you have a Julian Day Number (JDN) — a continuous integer count of days since the Julian Period — and need to convert it back to a human-readable Gregorian date with weekday information. Prefer this over date arithmetic libraries when you need a reliable, stateless, pay-per-use API call without managing dependencies. This is the inverse of the companion Gregorian-to-JDN endpoint on the same service.","instructions":null,"reviewSummary":null,"reviewSummaryHighlights":null,"reviewSummaryConcerns":null,"reviewSummaryGeneratedAt":null,"activationCount":0,"lastUsedAt":null,"lastSuccessfullyRanAt":null,"lastHealthCheckAt":"2026-09-15T00:46:58.284Z","isFirstParty":false}