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Try a phrase
Pick an example, or write your own.
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Expressions that add or subtract time from another date.
Change timezone or format
Words like “today” and “at noon” are calculated in this timezone.
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Developer tools
Sent to this site's server
Compare with the API
Compare the captured input below with the server. A request runs only when you choose Check API result.
Enter a phrase above to build a request.
Sends this expression, timezone, reference time and date format to Cloudflare. Avoid private information. Privacy details
API reference
GET /api/parse
Returns the date and calculation steps as JSON. No API key needed.
expressionRequired- The phrase to calculate. Up to 200 characters.
timezoneOptional- An IANA timezone, such as America/Chicago. Defaults to UTC.
referenceOptional- A starting instant with an offset, such as 2026-01-26T19:30:00Z. Defaults to the request time; reuse it to reproduce a result.
formatOptional- A date-fns display format, such as yyyy-MM-dd. Does not change the calculation.
Calendar rules
- Changes run in written order. Whole months and years clamp to the last valid day at each step.
- Whole days and weeks follow the local calendar. Their fractional parts use elapsed time.
- Fractional years become whole months first. Any remaining month or year fraction uses a labelled day approximation.
Limits and errors
About 120 requests per minute per IP at each Cloudflare location. HTTP 429 means wait a minute; HTTP 503 means try again shortly.
Invalid, unknown, or repeated parameters return HTTP 400. URLs over 4,096 characters return HTTP 414. Responses are not cached.
Engine v2 removed preserveDayOfMonth. Omit it from requests.