Cron with Seconds (6-Field) Generator & Analyzer
Build and analyze 6-field cron expressions with a seconds field — the format used by node-cron, Quartz and other application schedulers. Get plain-English explanations and exact next-run times.
Paste a cron expression to see what it means and when it runs next.
Common schedules
This schedule means
Next 5 run times
Field breakdown
Things to check
The seconds field is only supported by application schedulers (node-cron, Quartz, Spring, robfig/cron and similar) — not the standard Unix crontab. All analysis runs locally in your browser.
What It Does
This is the seconds-aware variant of the cron tool. It works with 6-field expressions whose first field is seconds, followed by the familiar minute, hour, day-of-month, month and day-of-week. That extra field unlocks sub-minute scheduling — every 5 seconds, every 30 seconds, or at a precise second of a chosen minute — which standard Unix cron cannot express. Paste an expression to get a plain-English description, the next five run times computed to the exact second in your local timezone, and a field breakdown; or switch to Build mode to assemble one from guided dropdowns and presets. Because the seconds field is only understood by application schedulers like node-cron, Spring and Quartz, the tool is designed for those environments rather than the system crontab.
When to Use It
- You are configuring node-cron, node-schedule or a Go/Java scheduler that expects a leading seconds field and want to verify the schedule.
- You need a job to run every few seconds and want to confirm the exact second-level timing before deploying.
- You inherited a 6-field expression and need to know whether the first number is seconds or minutes and what the schedule really does.
- You want sub-minute precision that the standard 5-field crontab simply cannot represent.
Worked Examples
*/30 * * * * *
Every 30 seconds — fires at second 0 and second 30 of every minute. The leading */30 is the seconds field; the rest are wildcards.
0 0 9 * * 1-5
At exactly 09:00:00, Monday through Friday. The first 0 pins the seconds, the second 0 the minutes, and 9 the hour.
15 30 8 * * *
Daily at 08:30:15 — a precise second-level daily trigger that a 5-field cron could not express.
*/5 * * * * *
Every 5 seconds, around the clock. Use sparingly: the job must finish in under 5 seconds to avoid overlapping runs.
Features
How to Use
Analyze: paste a 6-field expression (second minute hour day-of-month month day-of-week) and read the description, exact next-run times and warnings. Build: switch to the Build tab, set the seconds field plus the others using dropdowns or presets, then copy the result. The explanation updates live.
Common Mistakes
- Pasting a 6-field expression into a system crontab. Unix cron has no seconds field and will misread the whole line — use a scheduler that documents seconds support.
- Confusing the first field. In 6-field cron the first number is seconds, not minutes. 30 * * * * * is every minute at second 30, not every 30 minutes.
- Scheduling sub-second-impossible work. A job that runs every second but takes longer than a second to finish will overlap or queue up — make frequent jobs fast and idempotent.
- Forgetting the server timezone. Like all cron, the actual run time depends on the scheduler's timezone, not the one shown here.