Cron Expression Parser

Decode any cron expression before it bites you

Cron syntax is famously easy to misread — is 0 0 * * 0 midnight on Sunday, or something else? Getting it wrong means a job that fires at the wrong time, too often, or never. This parser translates any 5-field expression into plain English and lists the next 10 run times so you can verify the actual schedule before you commit it to a crontab or a cloud scheduler.

The five fields are minute, hour, day-of-month, month, day-of-week, and the key operators are * (every), , (list), - (range), and / (step). Everything runs in your browser.

Common cron patterns

• */15 * * * * — every 15 minutes
• 0 * * * * — every hour, on the hour
• 0 9 * * 1-5 — 9:00 AM every weekday
• 0 0 1 * * — midnight on the 1st of each month
• 0 0 * * 0 — midnight every Sunday

How to use it

1. Enter an expression or pick a preset.
2. Confirm the plain-English description matches your intent.
3. Check the next 10 run times (your local timezone) before deploying.

Related tools

• Building an expression from scratch? Use the Crontab Builder.
• Working with Unix timestamps? Try the Timestamp Converter.

Frequently asked questions

What do the five fields in a cron expression mean?

In order: minute (0–59), hour (0–23), day of month (1–31), month (1–12), and day of week (0–6, Sunday is 0). So "30 9 * * 1-5" runs at 9:30 every weekday. This tool translates any expression into plain English and shows the next run times so you can confirm it before deploying.

What do the special characters mean?

An asterisk (*) means "every" value for that field. A comma lists values (1,15). A hyphen is a range (1-5). A slash is a step (*/15 = every 15). So "*/15 * * * *" runs every 15 minutes, and "0 0 1,15 * *" runs at midnight on the 1st and 15th.

What timezone do cron expressions use?

Cron has no timezone of its own — it uses the system (or scheduler) timezone where it runs. The next-run times here are shown in your browser's local timezone. If your server runs in UTC, account for the offset, or your jobs will fire at a different wall-clock time than you expect.

What's the difference between 5-field and 6-field cron?

Standard Unix cron uses 5 fields (minute to day-of-week). Some systems (Quartz, some Kubernetes/cloud schedulers) add a leading seconds field for 6 fields, and others add a trailing year. This parser uses the standard 5-field syntax that crontab and most schedulers expect.

Why do day-of-month and day-of-week both exist?

They let you schedule by calendar date or by weekday. A subtle gotcha: in standard cron, if you set both to specific values (not *), the job runs when either matches, not both. Keep one as * unless you intentionally want that OR behavior.