How to Build a Cron Expression
A cron expression is five fields separated by spaces, read left to right: minute, hour, day of month, month, and day of week. Each field says whenin that unit the job should run. The hard part is never the syntax — it is being sure the expression means what you think, which is exactly what the plain-English readout and next-run list above are for.
Start from a preset
Pick the closest common schedule below, then adjust. Faster and safer than writing five fields blind.
Edit one field at a time
Change the minute or hour box and watch the English update instantly. If it turns red, that field is invalid.
Check the next runs
The real test. If the next five run times look right, the expression is right. Then copy it.
The Five Fields, In Order
Minute (0-59)
Which minute of the hour. 0 is the top of the hour, */15 is every quarter hour.
Hour (0-23)
Which hour of the day, in 24-hour time. 0 is midnight, 9 is 9am, 18 is 6pm.
Day of month (1-31)
Which date. Combine with month for a specific day, but mind that 31 does not exist everywhere.
Month (1-12)
Which month. Numbers or names both work, so 6 and jun are the same thing.
Day of week (0-6)
Which weekday. 0 is Sunday, 1 is Monday, and names like mon or fri also work.
The Four Symbols That Do Everything
* means every value of that field — a star in the minute field is every minute. , lists specific values, so 0,30 in minutes means on the hour and half past.
- is a range, so 1-5 in the weekday field is Monday through Friday. / is a step, so */15 is every fifteenth value. These nest — 0-30/10 is legal and means 0, 10, 20, 30.
The one genuine trap is that day-of-month and day-of-week combine with OR, not AND. If you restrict both, the job runs when either matches, not both together. So 0 0 13 * 5 runs on every 13th and every Friday, not only Friday the 13th. The next-run list above will catch this for you before it bites in production.
Frequently Asked Questions
What does a cron expression mean?
It is five fields — minute, hour, day of month, month, day of week — that together define a repeating schedule. This tool translates any expression into a sentence so you do not have to decode it in your head.
How do I run a cron job every 5 minutes?
Use */5 * * * *. The */5 in the minute field means every fifth minute; the stars mean every hour, day and month.
How do I schedule something for weekdays only?
Put 1-5 in the last field, as in 0 9 * * 1-5 for 9am Monday through Friday. 0 is Sunday and 6 is Saturday.
What is the difference between day-of-month and day-of-week?
Day-of-month is a date like the 1st; day-of-week is a weekday like Monday. If you set both, cron runs when either matches, which surprises people — the next-run list here shows the real behaviour.
Can I use month and day names instead of numbers?
Yes. jan through dec and sun through sat work in the month and weekday fields, so 0 9 * * mon-fri is valid.
Does this support seconds or six-field cron?
No. This uses standard five-field cron, which is what Linux crontab, most schedulers and CI systems use. Six-field variants that add seconds are not covered.
Is my expression sent to a server?
No. Everything is parsed and calculated in your browser. Nothing you type is uploaded or logged.
How do I run a job on the first of every month?
Use 0 0 1 * * for midnight on the 1st. Change the 0 0 to another time if you do not want midnight.
Why is my cron field showing red?
That field has a value outside its allowed range or a syntax it cannot parse — for example a minute above 59. Fix that one box and the readout returns.
What does */15 mean?
Every fifteenth value of that field starting from zero. In the minute field that is :00, :15, :30 and :45.
How do I know my cron expression is correct?
Read the plain-English line and check the next five run times. If those match what you intended, the expression is correct.
Is this cron builder free?
Yes, completely free with no signup, no limits and no premium wall.
Last updated: July 25, 2026 · FlipMyFormat Cron Expression Builder
Written and maintained by the FlipMyFormat team