What is a Crontab Guru?

Every sysadmin has a story about the cron job that ran at the wrong time. Cron expressions are five cryptic fields — minute, hour, day of month, month, day of week — and the syntax is old, terse, and full of traps: * means every, */5 means every fifth, and the difference between 0-5 in the day-of-week field meaning Sunday through Thursday is easy to get exactly backwards. This tool translates a cron expression into plain English, so you can verify what you actually scheduled rather than what you think you scheduled.

Type or paste an expression like 35 16 * * 0-5 and get back 'At 04:35 PM, Sunday through Friday'. Other examples: * * * * * is 'Every minute', */5 * * * * is 'Every 5 minutes', 0 12 1 * * is 'At 12:00 PM, on day 1 of the month'. Reading the English sentence aloud is often enough to catch the error immediately — 'every minute' when you meant 'every hour' jumps out in a way that the raw asterisks never do.

The tool is deliberately minimal: pure text in, plain English out, running instantly in your browser with nothing sent anywhere. It also helps in the reverse direction — when you are unsure how to express a schedule, experimenting with field values and watching the sentence update is faster than consulting a syntax table.

A classic boundary worth knowing: when both day-of-month and day-of-week are restricted (neither is *), cron runs the job when either matches, not both — one of the most surprising behaviors in the standard, and precisely the kind of thing an English translation makes visible.