Cron Expression Builder and Parser

Build and validate cron expressions for Unix, Quartz, and AWS/EventBridge. Includes a next-run preview when supported. Local only.

Unix cron (5 fields) Local only

Cron flavor

Different systems use different field counts and rules. Pick the one you need.

Fields: 5

Classic cron: minute hour day-of-month month day-of-week.

Builder

Choose a simple schedule, or switch to custom fields for advanced patterns.

Preseteasy mode

Minute0–59

Hour0–23

Output

Copy the cron expression for your scheduler.

Cron expression

0 9 * * *

Unix: 5 fields. Seconds/year are not used.

Quick help

Unix: 5 fields (no seconds).
Quartz: 6/7 fields (includes seconds), supports ? for day fields.
AWS/EventBridge: 6 fields wrapped in cron(...).

Supported syntax (this tool)

* any value
1,2,3 lists
1-5 ranges
*/10 steps
? (Quartz/AWS only) “not specified” for day fields

Not supported (yet)

This tool intentionally avoids advanced cron tokens that differ by implementation, like L, W, and #. If your platform uses those, you can still use the builder presets or simplify the expression.

Versions of cron (quick)

Unix (Vixie): 5 fields, day-of-month and day-of-week are typically ORed.
Quartz: 6/7 fields, expects one of day-of-month/day-of-week to be ?.
AWS/EventBridge: 6 fields + wrapper cron(...), requires ? on a day field.

How it works

Builder presets assemble tokens per flavor, the parser normalizes pasted expressions, and next-run preview scans future instants (seconds for Quartz, minutes for Unix/AWS) until five matches or a safety cap.

Nicknames like @daily are parsed but skip preview because platforms implement them differently.
Unsupported tokens (L, W, #) are rejected to avoid misleading schedules.

Quick examples

Unix weekday 9am

0 9 * * 1-5

Runs Mon–Fri at 09:00 (no seconds)

Quartz with seconds

30 15 6 ? * MON-FRI

06:15:30 on weekdays

For AWS/EventBridge paste cron(0 12 * * ? *) including the wrapper to match console exports.

Mini FAQ

Why no preview for nicknames?

Their schedules vary by platform; the tool avoids guessing.

Is Sunday 0 or 7?

Both are accepted on input; output normalizes to 0–6.

How far does preview search?

Up to 200k candidate times; very sparse schedules may stop early.