Cron Expression Parser and Next Run Times

Validate cron expressions and get a plain-English meaning, the parsed fields, the next run times in UTC and your time zone, and the previous run.

What it does

Paste one or more cron expressions and this Actor checks each one, explains it in plain English ("At 09:00, Monday through Friday"), splits it into its fields and lists the upcoming run times both in UTC and in the IANA time zone you choose. Expressions that do not parse still get a row with valid: false and the reason, so you can audit a whole crontab or a list of job schedules in one run.

Supported syntax:

• 5 fields: minute hour day-of-month month day-of-week, for example */15 * * * *.
• 6 fields with seconds first, for example */10 * * * * * or Quartz-style 0 30 8 ? * MON-FRI.
• Ranges, lists, steps, month and weekday names, L (last day), W (nearest weekday) and # (nth weekday, 5#2 = second Friday).
• ? in the day fields is accepted and treated like *.
• Macros: @yearly, @annually, @monthly, @weekly, @daily, @midnight, @hourly, plus @weekdays, @weekends, @minutely, @secondly.
• Extra spaces between fields are ignored.

Use cases

• Audit every schedule in a crontab, CI config or Kubernetes CronJob list and find the invalid ones in one run.
• Confirm a job fires at the right local time around a daylight saving change (set Start from to the change date).
• Turn cryptic expressions into plain-English descriptions for runbooks and documentation.
• Check that Apify schedules or other job schedules in different time zones do not overlap.

How to use it

1. Enter your expressions in Cron expressions, one per line.
2. Pick a Time zone (IANA name, default UTC).
3. Optional: set Number of next runs and a Start from moment.
4. Run the Actor.
5. Export the dataset as JSON, CSV or Excel, or read it through the Apify API.

Input

Field	What it does	Default	Example
expressions (required)	List of cron expressions, one per line	none	["*/15 * * * *", "0 9 * * 1-5", "@daily"]
timezone	IANA time zone the schedule is evaluated in; an unknown zone fails the run	UTC	Europe/Berlin
nextRunsCount	How many upcoming runs to list per valid expression, 1 to 100	10	24
fromDate	ISO 8601 moment to compute next and previous runs from	now	2026-03-08T00:00:00Z
maxItems	Stop after this many expressions	100	1000

Output

One row per expression. For 0 9 * * 1-5 in Europe/Berlin with 3 runs from 2026-11-03T00:00:00Z:

{
  "expression": "0 9 * * 1-5",
  "valid": true,
  "error": null,
  "description": "At 09:00, Monday through Friday",
  "timezone": "Europe/Berlin",
  "normalized": "0 0 9 * * 1-5",
  "hasSeconds": false,
  "fields": { "minute": "0", "hour": "9", "dayOfMonth": "*", "month": "*", "dayOfWeek": "1-5" },
  "nextRuns": [
    { "utc": "2026-11-03T08:00:00.000Z", "local": "2026-11-03T09:00:00+01:00" },
    { "utc": "2026-11-04T08:00:00.000Z", "local": "2026-11-04T09:00:00+01:00" },
    { "utc": "2026-11-05T08:00:00.000Z", "local": "2026-11-05T09:00:00+01:00" }
  ],
  "previousRun": { "utc": "2026-11-02T08:00:00.000Z", "local": "2026-11-02T09:00:00+01:00" },
  "intervalMinutes": null
}

Field	Meaning
valid, error	Whether the expression parses, and the reason when it does not
description	Plain-English summary of the schedule
normalized	The expression as 6 fields (seconds first), names turned into numbers and macros expanded
fields	The 5 standard fields; second is added when the expression has a seconds field
nextRuns, previousRun	Run times in UTC and in the chosen time zone
intervalMinutes	Set only when runs are evenly spaced (15 for */15 * * * *); null for uneven gaps such as weekdays only

An invalid expression gives a status row with valid: false, an error message such as Expected 5 fields ... got 4, and empty run fields. These rows are part of the audit result.

Pricing

Pay per result: $0.50 per 1,000 results ($0.0005 per result). You only pay for results the Actor returns. Set a maximum total charge on the run to cap your spend.

Limits

• 7-field Quartz expressions (with a year field) are reported as unsupported; drop the year to check the rest.
• @reboot has no schedule, so it is reported as not valid.
• Jenkins-style H and non-standard extensions of other schedulers may be read differently than your scheduler reads them.
• The English description is generated by a library and is a summary; the listed run times are the authoritative answer.
• At most 100 next runs per expression. intervalMinutes looks at the first 12 runs only.
• An empty expression list, an unknown time zone or an unreadable start date fail the run with no results.

FAQ

How much does it cost to check a crontab? One result per expression: 200 expressions cost $0.10. The number of next runs you list does not change the price.

Are invalid expressions charged? Yes, each expression gives one row, valid or not, because the valid: false row with its reason is the answer you asked for. A run with an unknown time zone or bad start date fails before any row and costs nothing.

How are daylight saving changes handled? Run times are computed in the IANA zone you choose, so a 0 2 * * * job in Europe/London shows +01:00 before the October change and +00:00 after it. Set Start from to just before the change to see it.

Can I compare runs with holidays? Yes. Get public holiday dates with the Plain Pipe Actor ICS Calendar Parser and iCal to JSON and check them against the nextRuns list.

Can I run it on a schedule or from my own code? Yes. Start runs through the Apify API, webhooks or integrations such as Make and Zapier, for example from a CI step that checks schedule changes before a deploy.

Legal and data

This Actor processes only what you give it or public, non-personal technical data. It does not log in anywhere, does not collect personal data, and does not bypass paywalls, CAPTCHAs or access controls. You are responsible for having the right to process the inputs you provide.

Support

Open an issue on the Issues tab. Issues are answered within 14 days.

Use this when: you need to validate a cron expression, explain it in plain English or see exactly when it will run next in a given time zone.

Why this one

• $0.50 per 1,000 results: one result per expression.
• Each row includes the normalized 6-field form, the parsed fields, next runs in both UTC and your IANA time zone, the previous run and an even-interval value in minutes.
• Accepts 5- and 6-field expressions, @daily-style macros and Quartz-style ?; pure computation with no browser, proxy or network access, and the prefill run finishes in a few seconds.
• The prefilled input is test-run daily.

Built and maintained by Plain Pipe.