Cron Job Calculator

Paste a cron expression. Get a sentence you can check, the next ten times it

will actually run, and a warning for every way it does not mean what it looks

like it means.

Everything is computed on your device. No account, no network, no upload.

Read it in plain English

"0 0 1 * MON" becomes "At 00:00, on day 1 of the month — and also on Monday,

since either day field matching is enough." The description is built from the

expression you typed, so a step stays a step and a range stays a range.

See the real times

The next runs, the last runs, and a countdown to the next one — in the time zone

your job runs in, not the one your phone is in. Pick any IANA zone.

Daylight saving, handled properly

Twice a year the wall clock does something a schedule cannot. An hour

disappears, and later an hour happens twice. A backup at 02:30 simply has no

02:30 to run at on the spring-forward date, and most schedulers lose the run

without logging anything.

This app resolves every occurrence against the full IANA database, marks the

runs that are skipped or repeated, and tells you what Vixie cron and cronie do

about it — and what systemd timers, Kubernetes CronJobs and library schedulers

do not.

The mistakes, before you make them

Both day fields set is an OR, not an AND — the most common cron mistake

Sunday is 0 in cron and 1 in Quartz, so the same digits mean a different day

"0 0 31 * *" runs seven times a year, not twelve

A step counts from the start of the field, so "*/25" leaves a ten-minute gap

A reversed range like "18-8" makes crontab reject the whole file

"5/10" is ordinary in Quartz and a syntax error in Vixie cron

Four dialects, and conversion between them

Unix (Vixie / cronie), the six-field form with seconds, Quartz, and AWS

EventBridge. Switch dialect and the app rewrites the expression — refusing,

with a reason, when the target genuinely cannot express the schedule.

Export to fourteen places

crontab, Kubernetes CronJob, systemd timer, GitHub Actions, GitLab CI, Jenkins,

Spring, Quartz, AWS EventBridge, Celery, node-cron, Go robfig/cron, Laravel and

APScheduler. Each snippet comes with what that target will and will not do:

GitHub Actions is UTC only, Kubernetes needs 1.27 for a time zone, Celery

intersects the day fields where cron unions them.

Day-of-week is always written as names in generated snippets, so the numbering

trap cannot survive a conversion.

Also

A visual builder, if you would rather not write the expression

45 presets, including six that exist to demonstrate a trap

An offline reference to the syntax, the dialects and the daylight-saving rules

Saved schedules and recent history

How often it runs: per year, per month, per week, and the shortest gap

Light and dark, following your system

Free, with ads.