Utilo

First Day of the Month Cron – Free, Online, Private

0 0 1 * * runs at 00:00 on the 1st of every month. Plain English: At 00:00, on day 1 of the month

Expression

Open in the cron parser · Cron builder

Next 5 runs (UTC)

The next runs appear when the expression parses.

crontab
0 0 1 * * /usr/local/bin/job
GitHub Actions
on:
  schedule:
    - cron: "0 0 1 * *"
Kubernetes CronJob
apiVersion: batch/v1
kind: CronJob
metadata:
  name: job
spec:
  schedule: "0 0 1 * *"
  timeZone: "Etc/UTC"
  jobTemplate:
    spec:
      template:
        spec:
          restartPolicy: OnFailure
          containers:
            - name: job
              image: busybox:1.36
              args: ["echo", "job"]

The expression

0 0 1 * * is a five-field cron expression: minute, hour, day of month, month, day of week. There is no seconds field and no year field. At 00:00, on day 1 of the month The next five run times on this page are computed in your browser with the same expression, in UTC, so a reload later in the hour shows a later list. Edit the box if you want to nudge a field and watch the list change, or open the line in the cron parser.

What each field is doing

The minute field is the single value 0. No other value in the 0–59 range matches. The hour field is the single value 0. No other value in the 0–23 range matches. The day-of-month field is the single value 1. No other value in the 1–31 range matches. The month field is an asterisk, so every value in the 1–12 range is allowed. This field is not what limits the schedule. The day-of-week field is an asterisk, so every value in the 0–6, Sunday as 0 or 7 range is allowed. This field is not what limits the schedule.

When the day-of-month and day-of-week fields are both something other than *, many cron implementations run the job if either field matches. This preset leaves at least one of those two fields as *, so you do not have to resolve that rule to predict it. Names such as MON and JAN are readable and widely accepted. The snippets use numbers so a strict parser does not have to know the names.

Why this schedule

Day-of-month 1 is the portable way to say the first of the month. The weekday field stays * so the job runs on the 1st even when the 1st is a Sunday. That is what invoices, usage resets, and monthly partitions usually want. It is not 'the first Monday'.

Opening a monthly partition, resetting a quota, sending an invoice, and freezing last month's numbers belong on the 1st. If the numbers are not ready at midnight, move the hour. Do not move the day to 2 and call it the first.

Where it goes wrong

The last day of the month is not expressible in classic five-field cron. Quartz uses L. This calculator does not promise L, W, or the # weekday modifier, because those tokens are not one behavior across cron daemons. Use the 1st, or name the day you mean. February's 1st is still day 1. There is no special case.

A sixth field is the seconds field used by Quartz, some Spring apps, and some Kubernetes setups that are not the classic CronJob schedule. Classic crontab, GitHub Actions, and the schedule field of a batch/v1 CronJob are five fields. If you paste a six-field line into those systems, the extra token shifts every field one place to the left and the job runs on a different day. L, W, and the # 'nth weekday' modifier are real in some daemons and rejected or reinterpreted in others. They are not used on this page. The English description and the next runs both refuse to guess at a token the calculator does not share with every target.

Crontab, GitHub Actions, and Kubernetes

GitHub Actions accepts this cadence. The schedule is UTC, it can start late when the service is busy, and it is dropped if the repository has had no activity for sixty days. The workflow file only needs the expression. It does not need a seconds field.

A user crontab does not include the username. A system crontab, the kind in /etc/crontab, inserts the user between the expression and the command. The line below is the user form. Kubernetes CronJob has used spec.timeZone since 1.27. The manifest sets it to Etc/UTC so the schedule matches the next-run list. Remove the field on a cluster older than that, and know that the schedule then uses the controller's zone.

crontab0 0 1 * * /usr/local/bin/job

GitHub Actionson:
  schedule:
    - cron: "0 0 1 * *"

Kubernetes CronJobapiVersion: batch/v1
kind: CronJob
metadata:
  name: first-day-of-month
spec:
  schedule: "0 0 1 * *"
  timeZone: "Etc/UTC"
  jobTemplate:
    spec:
      template:
        spec:
          containers:
            - name: job
              image: busybox:1.36
              args: ["echo", "first-day-of-month"]
          restartPolicy: OnFailure
  • Keep the command idempotent. Cron does not remember a failure and it does not skip a run that is already in progress.
  • Write the timezone next to the expression. UTC in the file and local time in the ticket are how a job fires eight hours early.
  • Offset the minute if several jobs would otherwise start at once.

Frequently asked questions

What does 0 0 1 * * mean?

First Day of the Month Cron is the five-field expression 0 0 1 * *. At 00:00, on day 1 of the month

Does 0 0 1 * * include a seconds field?

No. First Day of the Month Cron (0 0 1 * *) is minute, hour, day of month, month, and day of week. Add a seconds field only if the scheduler you are configuring documents six fields, and do not paste that six-field line into a five-field crontab.

Which timezone are the next runs of 0 0 1 * * shown in?

UTC. The next five times for First Day of the Month Cron are computed from 0 0 1 * * in UTC. GitHub Actions schedules are UTC. A server crontab uses the server's zone unless you set one. The Kubernetes snippet on this page sets timeZone to Etc/UTC.

Can I edit 0 0 1 * * on this page?

Yes. The box starts as 0 0 1 * *, the First Day of the Month Cron preset, and recomputes the English sentence and the next five UTC runs as you type. The cron parser and the cron builder open the same kind of five-field expression.