Cron Expression Builder & Tester
Validate a cron expression and see its next 5 run times, with presets for common schedules. Supports ranges, lists, and steps.
✓ Valid expression
Next 5 run times (UTC)
- 1. Mon, 25 May 2026 09:00:00 UTC
- 2. Tue, 26 May 2026 09:00:00 UTC
- 3. Wed, 27 May 2026 09:00:00 UTC
- 4. Thu, 28 May 2026 09:00:00 UTC
- 5. Fri, 29 May 2026 09:00:00 UTC
About this tool
Cron expressions schedule recurring jobs using five fields — minute, hour, day-of-month, month, and day-of-week — but the syntax is famously easy to get subtly wrong. This tool validates your expression and, more usefully, computes the next five times it will actually fire, so you can confirm the schedule does what you intend before deploying it. It supports the standard operators: * (every), ranges like 1-5, lists like 1,15,30, and steps like */15. Presets for the most common schedules give you a starting point. All times are computed in UTC for predictability — note that real cron daemons run in the server’s local timezone, so account for any offset. Use it to sanity-check a deployment cron, a CI schedule, or a database job.
How to use it
- Type a 5-field cron expression, or pick a preset.
- Confirm it validates.
- Read the next 5 run times to verify the schedule.
- Remember the times are UTC — adjust for your server timezone.
Frequently asked questions
- What are the five cron fields?
- In order: minute (0–59), hour (0–23), day-of-month (1–31), month (1–12), and day-of-week (0–6, where 0 is Sunday). For example, "0 9 * * 1-5" means 9:00 AM on every weekday.
- What do *, /, -, and , mean in cron?
- * matches every value; */n means every n units (e.g. */15 = every 15 minutes); a-b is a range (1-5 = Monday–Friday); and a,b,c is a list of specific values. They can be combined within a field.
- How do day-of-month and day-of-week interact?
- In standard cron, when both are restricted (not *), the job runs when either matches — an OR. This tool treats them with the common AND semantics for the next-run preview; if you set both, double-check against your specific cron implementation.
- Why are the times in UTC?
- For predictability, since cron behavior otherwise depends on the server’s timezone. Real cron daemons typically use the system local time, so if your server is not on UTC, shift the displayed times by your timezone offset.
- What is the difference from a 6-field cron?
- Some systems (like Quartz or some Linux setups) add a seconds field at the front, making six fields. This tool uses the classic five-field Unix cron format; drop the seconds field if your source has one.
- Does this run my job?
- No — it only parses and previews the schedule in your browser. It does not execute anything or connect to any server; it is purely for validating and understanding the expression.