How to use the Cron Expression Generator
- 1. Build or pastePick a schedule from the menus, or paste an expression.
- 2. Choose a time zoneSee run times in IST or UTC.
- 3. Check and copyRead the meaning, check the next 5 runs and copy the expression.
How to read a cron expression
A cron expression has five fields, separated by spaces:
minute hour day-of-month month day-of-week*means every value.,makes a list, like1,15.-makes a range, like1-5./sets a step, like*/15.
For example, 30 9 * * 1-5 means 9:30 AM, Monday to Friday. */15 9-17 * * 1-5 means every 15 minutes during working hours on weekdays. 0 0 1 * * means midnight on the first day of every month. Days of the week run from 0 for Sunday to 6 for Saturday, and 7 is also accepted as Sunday. Short names like MON and JAN work too.
Mistakes that catch people out
Time zone. Cron uses the server's clock, and many servers run on UTC. A job meant for 9:30 AM IST needs 0 4 * * * on a UTC server, because IST is 5:30 ahead. Switch the time zone here to compare.
Day of month and day of week together. If both are set, classic cron runs when either one matches, not both. So 0 0 13 * 5 runs on every 13th and also every Friday. The tool warns you about this.
Short months. A job set for the 31st skips months without that date. An impossible date like 31 February never runs, and the tool tells you so.
This tool covers standard 5-field cron. Tools with a seconds field, like Quartz, use a different format. Run times are worked out in your browser. To convert log times, use the timestamp converter.
Frequently asked questions
Does it support six-field cron?
No. It covers standard five-field cron, as used by Linux crontab and most schedulers. Formats with seconds, like Quartz, differ.
Why do my jobs run at the wrong time?
Your server is probably on UTC, not IST. Check the server's time zone and compare both in this tool.
Can it explain an expression I already have?
Yes. Choose Explain an expression and paste it to see its meaning and next 5 runs.
Is this tool free?
Yes, it is free. We ask for your name and WhatsApp number once when you see your result, and other Uncodemy tools then open without the form.