Cron Expression Parser and Explainer
Turn a crontab schedule into plain English and see its next runs.
minute · hour · day of month · month · day of week
Use via API
Explain a five-field cron expression and list its next run times (UTC). Send JSON, get JSON back.
POST https://pithlab.com/api/v1/tools/cron-expression-parser
curl https://pithlab.com/api/v1/tools/cron-expression-parser \
-H "Authorization: Bearer $PITHLAB_KEY" \
-H "Content-Type: application/json" \
-d '{"expression":"0 9 * * 1-5","count":3,"from":"2026-10-20T00:00:00Z"}'About the Cron Expression Parser
Explain any 5-field cron expression in plain English, catch syntax errors, and preview the next 10 run times in UTC or your local time zone.
How to use the Cron Expression Parser
- Type or paste a cron expression with five fields: minute, hour, day of month, month and day of week. Macros like @daily work too.
- Read the plain-English explanation, or the error message pointing at the field that is wrong.
- Check the next 10 run times, shown in UTC or your local time, to confirm the schedule fires when you expect.
Examples
Input
0 9 * * 1-5
Output
At 09:00 on Monday through Friday
Input
*/15 * * * *
Output
Every 15 minutes
Input
*/30 9-17 * * MON-FRI
Output
Every 30 minutes between 09:00 and 17:59 on Monday through Friday
Input
0 0 1 * 5
Output
At 00:00 on day 1 of the month or on Friday
Input
@weekly
Output
At 00:00 on Sunday
Frequently asked questions
What do the five cron fields mean?
In order: minute (0–59), hour (0–23), day of month (1–31), month (1–12 or JAN–DEC) and day of week (0–7 or SUN–SAT, where both 0 and 7 are Sunday). Each field accepts * for any value, lists like 1,15, ranges like 1-5 and steps like */10 or 9-17/2.
What happens if I set both day of month and day of week?
Standard cron runs the job when either one matches, not both. 0 0 1 * 5 runs on the 1st of every month and on every Friday. If either field starts with *, both must match instead.
Which time zone does cron use?
The time zone of the machine or service running it, which on servers and many cloud schedulers is UTC. That's why this tool shows the next runs in UTC by default; switch to local time to compare with your clock.
Does this support seconds or years?
No. Those six- and seven-field formats come from Quartz and some cloud schedulers, not standard cron. This tool checks the classic five-field format used by crontab, Kubernetes CronJobs and GitHub Actions.