Checking a crontab
Confirm a server job really runs when you think it does.
Cron Expression Explainer
Understand a crontab line at a glance. Runs in your browser.
Your files stay with you. Your files never leave your browser. This tool runs on your device: nothing is uploaded to our servers, so there is nothing for us to store or see.
How to use it
- Type or paste a 5-field cron expression, or pick an example.
- Read the plain-English meaning and the field breakdown.
- Check the next run times in your time zone.
Where it helps
CI and schedulers
Read schedules in GitHub Actions, Kubernetes CronJobs and app settings.
Time zones
See an IST time for a job that runs in UTC on the server.
Good to know
Stays in your browser
Everything is worked out on your device and never sent to our servers.
Servers often use UTC
A 9 am UTC job runs at 2:30 pm IST.
Standard 5 fields
Quartz and AWS syntax differ.
Questions people ask
How do you read a cron expression in plain English?
Type or paste a five-field cron expression, or pick an example such as every 5 minutes or weekdays at 9 am. The tool explains it in plain English, breaks down each field and lists the next five run times in India time, UTC or your device's zone. Shortcuts such as @daily and names such as MON-FRI work too.
- 5 fields Explained. Minute to weekday.
- Next 5 Run times. In IST or UTC.
- @daily Shortcuts. And MON-FRI, JAN.
- Warns Never runs. Like 31 February.
What are the five cron fields?
Minute (0-59), hour (0-23), day of month (1-31), month (1-12 or JAN-DEC) and day of week (0-6 or SUN-SAT, with 0 and 7 both meaning Sunday). A star means every value, */5 means every fifth, 1-5 is a range and 1,15 is a list. The tool breaks each field down for you.
What happens when both day fields are set?
In standard cron the job runs when either the day of month or the day of week matches, not only when both do. So 0 9 1 * MON runs at 9 am on the 1st of every month and on every Monday. That surprises many people, and the run times here show it clearly.
Does it support seconds or Quartz and AWS syntax?
No, only the standard five fields, plus shortcuts such as @daily and @hourly. Quartz, Spring and AWS EventBridge add a seconds or year field, or use ? and L in ways that differ. Check those schedules in their own documentation or console. A six-field expression gets a clear message here.
Which time zone do the run times use?
Your choice: India (IST), UTC or your device's zone. Remember that servers and cloud schedulers usually run cron in UTC unless configured otherwise, so a job written as 0 9 * * * may actually run at 2:30 pm in India. Compare the zones to be sure. Pick the zone your server uses.
How do I run a job every 15 minutes?
Use */15 * * * *. The */15 in the minute field means every fifteenth minute, so the job runs at :00, :15, :30 and :45 each hour. Type it in to see the next five runs. Use */5 for every five minutes or 0 * * * * for once an hour, on the hour.
How do I schedule a job on weekdays only?
Put MON-FRI, or 1-5, in the day of week field. 0 9 * * MON-FRI runs at 9 am Monday to Friday. Add a time zone check here, because 9 am on the server may not be 9 am in India. Indian public holidays aren't skipped; handle them in your job's code.
What do @daily, @hourly and similar shortcuts mean?
@hourly is 0 * * * *, @daily or @midnight is 0 0 * * *, @weekly is 0 0 * * 0, @monthly is 0 0 1 * * and @yearly is 0 0 1 1 *. They're easier to read but run at fixed times, such as midnight. Midnight UTC is 5:30 am in India, which is worth knowing.
Why does it say the schedule never runs?
Some expressions can never match a real date, such as the 31st of February or the 30th of February. The tool checks the next five years and warns you when nothing matches, instead of leaving you waiting for a job that will never start. Fix the day or month field.
How do I run a job on the last day of the month?
Standard cron has no 'last day' symbol. A common trick is to run on days 28 to 31 and have the script check whether tomorrow is the 1st before doing its work. Some schedulers, such as Quartz, support L for the last day, but this tool follows standard cron.
Can I use month and day names?
Yes. JAN to DEC work in the month field and SUN to SAT in the day of week field, in upper or lower case. Names make expressions easier to read, such as 0 10 * * SAT for 10 am every Saturday. Ranges such as MON-FRI work the same as 1-5.
Where is cron used?
On Linux servers through crontab, in GitHub Actions schedules, Kubernetes CronJobs, many hosting control panels and inside apps that run background tasks such as sending reminders, backups and reports. The five-field format is the same in most of these. Check which time zone each scheduler uses before relying on it.
Why didn't my cron job run?
Common reasons are a time zone mismatch, the cron service not running, a script that fails because cron has a smaller environment and PATH, or the day fields matching differently than you expected. Check the run times here first, then the server's logs for errors.
Can I check a GitHub Actions schedule?
Yes. GitHub Actions uses standard five-field cron and always runs in UTC. Paste the expression from your workflow file and choose UTC and IST to see when it really runs. Note that GitHub can delay scheduled runs at busy times, sometimes by several minutes. Don't rely on exact minutes.
Does it work on a phone?
Yes. Type or paste an expression on your phone, or tap an example, and read the explanation and the next five runs. It runs in any modern mobile browser with nothing to install, so you can check a schedule while you're reviewing code or an alert away from your desk.
Is the cron expression explainer free?
Yes. It's free with no sign-up and no limit on use. It's one of the free developer tools from Marketiism, along with the Unix timestamp converter and the regex tester. Marketiism builds software that runs scheduled WhatsApp reminders for businesses. Use it as often as you need.
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