Cron Expression Generator & Translator

A cron expression is a short string of five fields — minute, hour, day-of-month, month, and day-of-week — that tells the cron daemon exactly when to run a scheduled job. Each field accepts a number, a wildcard (*), a comma-separated list, a range (a-b), or a step (*/n). For example, 0 9 * * 1-5 means "at 09:00, Monday through Friday."

Crontab ("cron table") is the file that stores a user's scheduled jobs, and crontab is also the command — crontab -e to edit, crontab -l to list — used to manage it on Linux and Unix systems. The cron daemon reads every user's crontab once a minute and runs any job whose cron expression matches the current time.

Cron is the background daemon that checks the schedule every minute and executes due jobs. Crontab is the file format and command-line tool used to define what cron should run and when. In short: cron is the engine, crontab is the schedule you hand it.

Use the cron expression */5 * * * * in your crontab. The */5 step syntax in the minute field means "every 5th minute," so the job fires at :00, :05, :10, and so on. The cheat sheet above has this pre-built for every 5, 10, 15, and 30-minute interval — just click "Use."

A persistent crontab is one that keeps running across reboots and process restarts, rather than a cron job defined only in a temporary shell session. On a normal Linux server, crontab entries are written to /var/spool/cron and persist automatically as long as the cron daemon starts on boot. The common gotcha is ephemeral environments — bare Docker containers, serverless functions, or short-lived VMs — where no cron daemon runs persistently unless you explicitly configure one or use an always-on host.

Standard Unix cron uses 5 fields (minute, hour, day-of-month, month, day-of-week). Quartz cron, used by Java schedulers and Spring Boot, adds a seconds field at the front (and an optional year field at the end), making 6 or 7 fields total. Quartz also requires exactly one of day-of-month or day-of-week to be a literal question mark (?), since standard cron's OR-logic between those two fields doesn't apply in Quartz.

No. Standard Unix cron numbers day-of-week 0-6 (0 = Sunday), with 7 also accepted as Sunday. Quartz cron numbers day-of-week 1-7, where 1 = Sunday and 7 = Saturday. This one-position offset is a common source of off-by-one scheduling bugs — using day names (SUN, MON, TUE...) instead of numbers sidesteps the ambiguity entirely, which is why this generator defaults to names in Quartz mode.

In standard Unix cron, if both day-of-month and day-of-week are restricted (neither is *), the job runs when EITHER condition is true — it's an OR, not an AND. For example, 0 0 1 * 1 runs at midnight on the 1st of the month OR every Monday, not only on Mondays that happen to fall on the 1st. This is a well-known cron gotcha that trips up a lot of scripts.

A cron job runs in the system timezone of the machine (or container) executing it, not in the timezone of whoever wrote the expression. Most managed servers and Docker base images default to UTC. This tool's "next run" preview uses your browser's local timezone for readability, but always double-check the actual server timezone (via the TZ environment variable or timedatectl) before relying on exact run times in production.

Yes. n8n's Schedule Trigger node has a "Custom (Cron)" mode that accepts a standard 5-field cron expression, with an optional 6th leading field for seconds (n8n's own docs give */10 * * * * * as "every 10 seconds"). Use this generator's Standard mode output directly in n8n; if you need sub-minute precision, prepend a seconds value. n8n does not require the Quartz-style ? exclusivity character — stick to standard cron syntax when pasting into n8n.

Not yet. L (last day), W (nearest weekday), and # (nth weekday of the month) are Quartz/AWS EventBridge extensions used for patterns like "last Friday of the month." This generator will parse and describe expressions containing them without crashing, but next-run calculation for those specific fields isn't supported yet.

Yes. The OpenHosst Cron Expression Generator is completely free, requires no sign-up, and runs entirely in your browser — no expression you build or paste is sent to any server.