Systemd Timer Generator | OnCalendar Tester

Systemd timer generator and OnCalendar tester. Build a .timer unit, see the normalized form and next elapse times like systemd-analyze calendar, in any zone. Designed specifically for developers and professionals, this free online generator runs entirely in your browser to process tasks quickly and securely. Enjoy unlimited usage with no data tracking and no registration required.

Also known as: systemd timer generator · systemd oncalendar generator · oncalendar syntax · systemd oncalendar examples · systemd timer every 5 minutes · systemd-analyze calendar online · systemd timer unit file · oncalendar tester · systemd timer vs cron

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OnCalendar Input

OnCalendar expression

Server time zone

Unit name

Description

RandomizedDelaySec

Persistent=true

OnCalendar shape

[weekdays] [year-month-day] [hour:minute:second] [time zone]

Use .. for ranges (Mon..Fri, 08..17), / for repeats (*:0/15), and ~ to count from the end of the month (*-*~01 is the last day). Without a time zone, systemd uses the server's local time.

Timer Unit Output

Enter an OnCalendar expression and run Generate Timer to see the next elapse times and a ready-to-use .timer unit.

About Systemd Timer Generator

A systemd timer generator turns an OnCalendar schedule into a ready-to-install .timer unit, the modern replacement for a crontab line on Linux servers. Type an expression such as Mon..Fri 09:00 and the tool validates it, prints the normalized form exactly as systemd-analyze calendar would, and lists the next ten elapse times in your server's time zone, including what happens across daylight saving changes.

Key Features

Parses the full OnCalendar grammar from systemd.time(7): weekdays, dates, times, lists, .. ranges and / repeats
Prints the same normalized form as systemd-analyze calendar, checked against systemd 257
Lists the next 10 elapse times in the server time zone or a zone written in the expression
Handles ~ end-of-month syntax, such as *-*~01 for the last day and Mon *-05~07/1 for the last Monday of May
Expands minutely, hourly, daily, weekly, monthly, quarterly, semiannually and yearly shorthands
Generates the .timer unit with Persistent= and RandomizedDelaySec=, plus the systemctl commands to enable it

Use Cases

Replacing a root crontab entry on an Ubuntu server with a systemd timer you can inspect with systemctl list-timers
Scheduling a nightly Postgres backup to S3 at 2:30 AM Central on an EC2 instance in us-east-2
Checking that a timer on a UTC server fires at 9 AM Eastern after the November clock change
Building a first-Monday-of-the-month maintenance window without writing shell date logic
Spreading a fleet-wide job across machines with RandomizedDelaySec so they do not all hit the API at once

Supported Formats

Calendar events: [weekdays] [year-month-day] [hour:minute:second] [time zone]

Weekday names in short or long form (Mon, Monday), lists and .. ranges

Lists, .. ranges and / repetitions in every date and time field, plus fractional seconds

Time zones: UTC or any IANA name such as America/New_York

Related Keywords

systemd timer generator

systemd oncalendar generator

oncalendar syntax

systemd oncalendar examples

systemd timer every 5 minutes

systemd-analyze calendar online

systemd timer unit file

oncalendar tester

systemd timer vs cron

How do I run a systemd timer every 5 minutes?

Use OnCalendar=*:0/5, which systemd normalizes to *-*-* *:00/5:00: every day, every hour, starting at minute 0 and repeating every 5 minutes. If you want every 5 minutes counted from when the machine booted or the last run finished instead of on the clock, use OnBootSec=5min with OnUnitActiveSec=5min. And add Persistent=true to a calendar timer if a run missed while the server was off should happen at the next boot.

Runs entirely in your browser

Expressions are parsed and elapse times calculated locally in JavaScript using your browser's time zone data. Nothing is uploaded, so unit names and descriptions from production hosts stay on your machine.

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Frequently asked questions

What is Systemd Timer Generator used for?

Systemd timer generator and OnCalendar tester. Build a .timer unit, see the normalized form and next elapse times like systemd-analyze calendar, in any zone.

Is Systemd Timer Generator free to use?

Yes. Systemd Timer Generator is completely free with no usage limits, and there is no paid tier required to use it.

Do I need an account to use Systemd Timer Generator?

No. Systemd Timer Generator works immediately in your browser with no signup, login, or email address required.

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