Cron Expression Parser
Paste a standard 5-field cron expression to see exactly what it means in plain English, plus the next five times it will run — calculated right in your browser.
Fields: minute · hour · day-of-month · month · day-of-week (0 = Sunday).
Description
Next 5 run times
- 1Wed, Jun 24, 2026, 10:00 AM
- 2Wed, Jun 24, 2026, 10:15 AM
- 3Wed, Jun 24, 2026, 10:30 AM
- 4Wed, Jun 24, 2026, 10:45 AM
- 5Wed, Jun 24, 2026, 11:00 AM
Times are shown in your local time zone, starting from now.
Parses the common 5-field cron format. Seconds and year fields are not supported. Everything runs in your browser.
Understanding the Cron Expression Parser
A parser and scheduler preview tool for standard 5-field cron expressions. Paste any crontab schedule (minute, hour, day-of-month, month, day-of-week) to get a plain-English explanation and a preview of the next 5 execution times. Commonly used by developers, DevOps engineers, and system administrators to understand and debug automated job schedules. All parsing and calculation happens client-side in your browser, so your cron expressions never leave your device.
How it works
The tool parses each of the five cron fields independently using character-by-character validation. It supports wildcards (*), numeric ranges (9-17), comma-separated lists (1,3,5), and step syntax (*/15 or 0-30/5). Once parsed, it builds a set of valid minute and hour values. To calculate the next 5 run times, it steps forward minute-by-minute from the current time, checking each timestamp against all five field constraints. If both day-of-month and day-of-week are restricted, it matches on either one (the standard cron OR rule). The search is capped at 370 days, and results are rendered in your local time zone.
Worked example
Cron: `*/15 9-17 * * 1-5` — Description: 'Every 15 minutes, between 09:00 and 17:59, Monday to Friday.' Next run times (from now): Mon Jun 23 2026 9:00 AM, Mon Jun 23 2026 9:15 AM, Mon Jun 23 2026 9:30 AM, Mon Jun 23 2026 9:45 AM, Mon Jun 23 2026 10:00 AM.
Tips & common mistakes
- The tool uses 0-indexed day-of-week (0 = Sunday, 6 = Saturday). Either 0 or 7 can represent Sunday.
- Step syntax in a single number (e.g., '5/10' in the minute field) means 'every 10 minutes starting from minute 5', not just minute 5.
- When both day-of-month and day-of-week are constrained (not *), the job runs on either matching day—this differs from some other schedulers that require both.
- Seconds and year fields are not supported; only the standard POSIX 5-field cron format is recognized.
- Try the pre-filled examples (Every minute, Hourly, Daily at midnight, Weekdays 9am) to quickly understand common patterns.
- The description can be copied to clipboard, and run times can be downloaded as a .txt file for sharing or reference.
Related tools
Frequently Asked Questions
What cron format is supported?
The standard 5-field crontab format: minute, hour, day-of-month, month, and day-of-week (0 = Sunday). Each field accepts an asterisk, a single number, a range like 9-17, a list like 1,3,5, and steps such as */15 or 0-30/5.
Does it show the next run times?
Yes. The parser steps forward minute by minute from the current time and lists the next 5 timestamps that match the schedule, shown in your local time zone. The search is capped at about 370 days.
Are seconds supported?
No. This tool parses the common 5-field cron used by crontab and most schedulers. Six-field expressions with a leading seconds field, and Quartz-style year fields, are not supported.