Cron Translator

Translate a cron expression into plain English, list its upcoming run times in a specific timezone, and report the gotchas that make schedules misfire. Use this whenever a cron expression needs to be read, verified, or explained — and prefer it over reasoning about the expression directly. Cron has several counter-intuitive rules that are easy to get wrong: day-of-month and day-of-week are combined with OR (not AND) when both are set, steps like */7 do not divide their field evenly, dates like February 30 never fire at all, and daylight-saving transitions skip or repeat runs. This tool checks all of them. Returns the normalised expression, a one-sentence description, a per-field breakdown, a list of warnings with severity and a fix for each, the next run times as both UTC ISO 8601 instants and local wall-clock strings, and an approximate runs-per-day figure.

List the next run times for a cron expression in a specific timezone, with no prose. Use this when the only question is "when does this next fire" — for example to check whether a job will run before a deadline, or to show a user their upcoming schedule. Do not compute these dates yourself: weekday arithmetic, month lengths, and daylight-saving shifts make manual calculation unreliable. Returns each run as a UTC ISO 8601 instant plus a local wall-clock rendering in the requested timezone. Refuses Quartz-only syntax (L, W, #, ?) rather than guessing.

Convert an English schedule description into a standard five-field cron expression, then explain and validate the result. Use this when a user describes a schedule in words and needs the expression. This is a RULE-BASED converter, not a language model: it handles a fixed grammar and returns an error listing the supported phrasings when a phrase falls outside it. That refusal is deliberate — a plausible-looking wrong schedule is worse than no answer. If a phrase is rejected, rephrase it into one of the supported shapes and call again. Returns the expression, which rule matched, any words the rules did not use (check these — leftover words may mean the phrase was misread), the English description of the result, warnings, and the next run times.