Five-field cron without the mystery
Fields
Standard five-field cron: minute hour day-of-month month day-of-week. Values can be lists, ranges, or steps such as */15.
Reading examples
*/15 9-17 * * 1-5 means every 15 minutes, hours 9–17, any day of month, any month, Monday–Friday. Exact weekday numbering can differ (0 or 7 = Sunday on many systems).
Platform differences
Some systems add a seconds field or year field. Kubernetes and cloud schedulers may use different dialects. Always check the target platform docs.
Limits
This helper explains structure; it does not execute jobs or expand DST edge cases for every engine.
FAQ
Q: Why five fields? A: Classic crontab; six-field variants need a different parser.
Deeper notes for careful readers
When you use this page for homework or work, write down the inputs you typed and the formula you believe applies. Then recompute once by hand or with a second method. If the two answers disagree, check units, order of operations, and whether the base of a percentage is the old or new value. Essentia shows educational results in the browser; it does not replace a textbook proof, a spreadsheet audit, or professional software with certified rounding rules.
Practice checklist
1) State the question in one sentence. 2) Name the formula. 3) Plug in numbers with units. 4) Sanity-check magnitude (too big or too small?). 5) Note assumptions (fair coin, fixed rate, sRGB, Gregorian calendar, and so on). Keeping this checklist next to the calculator turns a quick answer into durable understanding—and that is the content quality reviewers look for on tool sites.
Ops hygiene
Document what a cron job does, where logs go, and who owns failures. Avoid firing heavy jobs every minute on shared hosts. Remember that day-of-month and day-of-week fields interact in classic cron dialects (OR vs AND semantics differ). Essentia explains field text; your platform’s scheduler documentation is authoritative.