Cron Expression Examples You Can Copy and Test Locally

A cron expression is five fields: minute, hour, day of month, month, day of week. */5 * * * * runs every 5 minutes, 0 9 * * 1-5 runs at 9:00 on weekdays, and 0 0 1 * * runs at midnight on the first of each month. Everything below uses that standard five-field format, as documented in the crontab(5) manual page.

The examples are grouped by what you're trying to do. Further down is a small matcher you can run to see when any expression fires, and a list of the mistakes that bite people most often. Other schedulers (cloud services, Java libraries, CRMs) have their own variations on this syntax, so check their docs before pasting an expression across.

The five fields at a glance#

┌──────── minute        0-59
│ ┌────── hour          0-23
│ │ ┌──── day of month  1-31
│ │ │ ┌── month         1-12 (or jan-dec)
│ │ │ │ ┌ day of week   0-7 (0 or 7 is Sunday, or sun-sat)
* * * * *  command

Four pieces of syntax cover almost everything:

• * means "first to last" for that field.
• a-b is an inclusive range. 8-11 in the hours field means 8, 9, 10 and 11.
• a,b,c is a list. Lists can contain ranges, like 0-4,8-12.
• /n is a step. It works after a range (0-23/2) or after an asterisk (*/2).

Month and weekday names are allowed (first three letters, case doesn't matter), including ranges and lists: mon,wed,fri, jan-mar.

Cron expression examples: every N minutes and hours#

The most common search is "every 5 minutes", so here it is, with its relatives.

A complete crontab line adds the command after the fifth field:

*/5 * * * * $HOME/bin/check.sh >> $HOME/tmp/check.log 2>&1

Redirecting output matters. Unless you set MAILTO="", cron mails whatever the job prints to the crontab's owner.

Weekdays, weekends and specific days#

Sunday can be written as 0 or 7. I'd use names (sun, mon-fri) in anything a teammate will read later, since 1-5 makes people count on their fingers.

Monthly, yearly and month-end schedules#

There are also nicknames that replace all five fields: @reboot (once after reboot), @yearly and @annually (0 0 1 1 *), @monthly (0 0 1 * *), @weekly (0 0 * * 0), @daily (0 0 * * *) and @hourly (0 * * * *).

Last day of the month is the one people ask for that standard cron can't express directly. The day-of-month field has no "last" value. A common workaround is to schedule the job for days 28 to 31 with 0 0 28-31 * *, then have the script itself check whether tomorrow is the first and exit if it isn't. The matcher below shows why you need that guard: the expression fires on four days in a 31-day month.

Timezone, environment and the percent sign#

The CRON_TZ variable sets the time zone for a crontab. You write times in that zone, while the daemon's log file uses the local zone of the machine. The manual's own example is:

CRON_TZ=Japan
5 0 * * * $HOME/bin/daily.job >> $HOME/tmp/out 2>&1

A few other details that explain odd behavior:

• Cron runs commands with /bin/sh unless you set SHELL in the crontab. HOME can also be overridden; LOGNAME can't.
• Environment lines look like name = value. Comments must be on their own line. A # after a command is treated as part of the command.
• A bare % in the command is turned into a newline, and everything after the first one is sent to the command as standard input. Escape it with a backslash: date +\%s.
• System crontabs (/etc/crontab and files in /etc/cron.d/) need a username between the schedule and the command:

MAILTO=root
* * * * * root touch /tmp/file

Test any schedule with a runnable matcher#

This script parses a five-field expression (or a nickname) and prints the next few run times from a fixed start date. It follows the rules from the manual: ranges, lists, steps, names, Sunday as 0 or 7, and the either-or rule for the two day fields. The start date is fixed so the output is reproducible. Edit the list and try your own expressions.

from datetime import datetime, timedelta

MONTHS = "jan feb mar apr may jun jul aug sep oct nov dec".split()
DAYS = "sun mon tue wed thu fri sat".split()
NICK = {"@yearly": "0 0 1 1 *", "@annually": "0 0 1 1 *",
        "@monthly": "0 0 1 * *", "@weekly": "0 0 * * 0",
        "@daily": "0 0 * * *", "@hourly": "0 * * * *"}

def value(tok, names, base):
    tok = tok.lower()
    return names.index(tok) + base if tok in names else int(tok)

def field(text, lo, hi, names=(), base=0):
    out = set()
    for part in text.split(","):
        rng, _, step = part.partition("/")
        stepped = bool(step)
        step = int(step) if step else 1
        if rng == "*":
            a, b = lo, hi
        elif "-" in rng:
            x, y = rng.split("-")
            a, b = value(x, names, base), value(y, names, base)
        else:
            a = value(rng, names, base)
            b = hi if stepped else a
        if a > b or a < lo or b > hi:
            raise ValueError("bad field: " + text)
        out.update(range(a, b + 1, step))
    return out

def parse(expr):
    parts = NICK.get(expr, expr).split()
    if len(parts) != 5:
        raise ValueError("need 5 fields: " + expr)
    return {
        "min": field(parts[0], 0, 59),
        "hour": field(parts[1], 0, 23),
        "dom": field(parts[2], 1, 31),
        "mon": field(parts[3], 1, 12, MONTHS, 1),
        "dow": {v % 7 for v in field(parts[4], 0, 7, DAYS, 0)},
        "dom_star": parts[2].startswith("*"),
        "dow_star": parts[4].startswith("*"),
    }

def day_ok(p, day):
    dom_ok = day.day in p["dom"]
    dow_ok = day.isoweekday() % 7 in p["dow"]
    if p["dom_star"] or p["dow_star"]:
        return dom_ok and dow_ok
    return dom_ok or dow_ok  # both restricted: either may match

def runs(expr, start, count=5):
    p = parse(expr)
    day = start.replace(hour=0, minute=0, second=0, microsecond=0)
    found = []
    for _ in range(800):
        if day.month in p["mon"] and day_ok(p, day):
            for h in sorted(p["hour"]):
                for m in sorted(p["min"]):
                    t = day.replace(hour=h, minute=m)
                    if t > start:
                        found.append(t)
                        if len(found) == count:
                            return found
        day += timedelta(days=1)
    return found

start = datetime(2026, 10, 14, 12, 0)
print("start:", start.strftime("%a %Y-%m-%d %H:%M"))
for expr in ["*/5 * * * *", "*/35 * * * *", "0 9 * * 1-5",
             "0 0 28-31 * *", "30 4 1,15 * 5", "@monthly", "0 0 31 2 *"]:
    times = runs(expr, start)
    shown = ", ".join(t.strftime("%a %m-%d %H:%M") for t in times)
    print(expr.ljust(15), shown or "never")

The expressions in the list are chosen to show the gotchas in the next section. Compare what */35 and 30 4 1,15 * 5 actually produce with what you'd guess from reading them.

Common mistakes and gotchas#

Steps restart inside each field. */35 in the minute field doesn't mean every 35 minutes. It means minutes 0 and 35 of every hour, so the gap alternates between 35 and 25 minutes. Likewise */23 in the hours field fires at hour 0 and hour 23 of each day. For true intervals, the manual suggests running every minute and testing the clock in the command:

* * * * * if [ $(expr \( $(date +%s) / 60 \) % 58) = 0 ]; then echo this runs every 58 minutes; fi

Two restricted day fields mean OR, not AND. If neither the day-of-month nor day-of-week field is *, the job runs when either matches. 30 4 1,15 * 5 runs at 04:30 on the 1st and 15th, plus every Friday. If you wanted "Fridays that fall on the 1st or 15th", cron can't say that; check the date inside the script.

Daylight saving time skips and repeats jobs. Times that don't exist during the spring change never match, so a job scheduled in that gap doesn't run. Times that happen twice in autumn cause matching jobs to run twice. If a job must run exactly once, schedule it outside the changeover hour or make it idempotent.

An unescaped % truncates your command. date +%F in a crontab breaks, because everything after the % becomes standard input. Write \%.

Missing trailing newline. Each crontab entry must end in a newline. If the last line ends at end-of-file, cron treats the crontab as at least partly broken and writes a warning to syslog.

Trailing comments. */5 * * * * run.sh # every five passes the comment to the shell as part of the command. Put comments on their own line.

Wrong file format. A line in /etc/crontab or /etc/cron.d/ without a username will try to run the first word of your command as the user. A line in a personal crontab with a username will try to run the username as the command.

You can also check syntax before installing a crontab with the -T option; see crontab(1) for details.

Quick reference checklist#

• Five fields, in order: minute, hour, day of month, month, day of week.
• "Every 5 minutes" is */5 * * * *. Steps only work within one field, so 35, 58 and similar numbers won't give even gaps.
• Weekdays: 1-5 or mon-fri. Sunday is 0 or 7.
• No "last day of month". Use 28-31 and guard in the script.
• Both day fields restricted means OR.
• Escape % as \%. Keep comments on their own lines.
• Set CRON_TZ if the schedule is in a specific zone, and remember the log file uses the machine's local time.
• Redirect output or set MAILTO so a noisy job doesn't flood a mailbox.
• Don't schedule anything important in the daylight saving changeover hour.
• Run the expression through the matcher above before you install it.

For the full list of variables and edge cases, the crontab(5) page on man7.org is short and worth reading once.

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