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Cron Expression Calculator

Cron Expression Calculator

Decode a cron schedule into plain English and see the exact upcoming run times in your timezone.

Decode a cron schedule into plain English and see the exact upcoming run times in your timezone.

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Cron Expression Calculator

What this calculator does

Takes a standard 5-field cron expression and turns it into a plain-English description of the schedule, then computes the exact upcoming run times in the timezone you choose. Useful for checking a crontab entry, a CI/CD scheduled pipeline, or a serverless cron trigger before you deploy it.

Cron expression format

A cron expression has five space-separated fields:

minutehourday-of-monthmonthday-of-week\text{minute} \quad \text{hour} \quad \text{day-of-month} \quad \text{month} \quad \text{day-of-week}
Field Allowed values
Minute 0-59
Hour 0-23
Day of month 1-31
Month 1-12
Day of week 0-7 (0 and 7 both mean Sunday)

Each field supports:

  • * — any value
  • 5 — an exact value
  • 1-5 — a range (inclusive)
  • */15 or 1-30/5 — a step, optionally within a range
  • 1,3,5 — a comma-separated list of values, ranges, or steps

If both day-of-month and day-of-week are restricted (not *), a run happens whenever either field matches — this mirrors standard cron behavior.

How the next run times are computed

The calculator shifts the current time into the timezone you selected, then walks forward minute by minute (up to one year ahead) checking each field against the wall-clock time, collecting matches until it has as many upcoming runs as you asked for.

LocalTime=CurrentUTCTime+TimezoneOffset\text{LocalTime} = \text{CurrentUTCTime} + \text{TimezoneOffset}

How to use it

  1. Enter a cron expression, e.g. */15 9-17 * * 1-5 (every 15 minutes, 9 AM-5 PM, Monday to Friday).
  2. Choose how many upcoming run times you want to see (1-20).
  3. Pick your timezone.
  4. Submit to see a plain-English description of the schedule and a table of the next matching run times.

Example

30 2 1 * * means:

  • Minute 30, hour 2 → 2:30 AM
  • Day-of-month 1 → the 1st of the month
  • Month * → every month
  • Day-of-week * → not restricted

Description: "At 02:30, on day 1 of the month" — this expression runs once a month, at 2:30 AM on the 1st.

Notes

  • Only the standard 5-field cron syntax is supported (no seconds field, and no non-standard shortcuts like @daily or L/W/#).
  • If an expression can't match any date in the next year (e.g. a day-of-month and month combination that never occurs, such as 0 0 30 2 *), the upcoming-runs table will be empty.