Cron Expression Explainer.

Cron expressions are the small alphabet Unix uses to schedule recurring jobs — five fields for minute, hour, day-of-month, month, and day-of-week, plus glyphs like *, ,, -, and / to express ranges and steps. The syntax is dense by design: 0 9 * * 1-5 reads as 9am on weekdays once you have parsed it, but it never tells you when the next run actually is. This explainer does both jobs at once. Paste any standard five-field cron, or one of the named aliases like @hourly or @daily, and you will see a plain-English description alongside the exact next five run timestamps in your local timezone or UTC.

Reach for it when you have inherited an unfamiliar crontab and want to confirm what you are about to commit, when you are writing a Kubernetes CronJob or a GitHub Actions schedule and want to sanity-check the cadence, or when you are debugging why a job did not fire last night by reading what the schedule actually said. Parsing happens in your browser — no values leave the page.