Guide: Cron Expression Parser
↑ Back to toolWhat is this tool?
This cron expression parser takes a standard 5-field cron expression and explains it in plain English. It shows a color-coded field breakdown (minute, hour, day, month, weekday with valid ranges), computes the next scheduled run times (5, 10, 20, or 50) in your local timezone, and includes a live clock so you can see how soon the next run is. The tool also provides 10+ common presets, 15 real-world cron job examples, and a built-in syntax reference table. You can copy the explanation and schedule to share with your team. All processing runs client-side.
Why use a cron parser?
Cron expressions are powerful but notoriously easy to get wrong. A misplaced number can mean your backup runs hourly instead of daily, or your report is sent on Monday at 3 AM instead of Sunday at 3 PM. This tool gives you instant visual feedback: see the breakdown of each field, read a human-readable explanation, and verify the exact upcoming execution times—all before you deploy.
Verify Before Deploy
- • See next 5–50 execution dates in your timezone
- • Catch off-by-one errors in day/month fields
- • Confirm the schedule matches your intent
Learn & Share
- • Read plain English explanations of any expression
- • Use presets to learn common patterns
- • Copy explanation to share with teammates
Key features
- Plain English explanation — Translates the cron expression into a readable sentence (e.g. "Every 5 minutes" or "At 09:00, Monday through Friday").
- Next run times — Computes and displays the next 5, 10, 20, or 50 execution dates/times in your browser's local timezone.
- Field breakdown — Color-coded fields with labels (minute, hour, day of month, month, day of week) and their valid ranges.
- 10+ common presets — One-click buttons for popular schedules: every minute, every 5 minutes, every hour, daily at midnight/noon, weekdays at 8 AM, first of month, and more.
- 15 real-world examples — Clickable cron job examples with descriptions (nightly backup, health check, standup reminder, billing run, SSL cert check, etc.).
- Live clock — Shows the current time and timezone so you can see exactly how soon the next run is (e.g. "in 3m 24s").
- Syntax quick reference — Built-in table explaining
*,,,-, and/with examples. - Copy explanation — Copy the expression, plain English explanation, and next runs as text to share with your team.
- Error detection — Shows a clear error message for invalid expressions (wrong number of fields, invalid values).
- 100% client-side — Runs entirely in your browser using the cron-parser library.
How this tool works (step-by-step)
- Type or select a cron expression — Enter a 5-field cron expression or click a preset/example.
- See the field breakdown — Each field is labeled with its name, value, and valid range, color-coded for quick scanning.
- Read the explanation — A human-readable description appears instantly below the input.
- Check next runs — The next 5–50 scheduled execution times appear in your local timezone. The first run shows a relative countdown.
- Copy — Copy the expression, explanation, and schedule to share with your team.
Common cron expression examples
| Expression | Meaning |
|---|---|
| * * * * * | Every minute |
| */5 * * * * | Every 5 minutes |
| 0 * * * * | Every hour (at minute 0) |
| 0 0 * * * | Every day at midnight |
| 0 9 * * 1-5 | Weekdays at 9:00 AM |
| 30 4 * * 0 | Sunday at 4:30 AM |
| 0 0 1 * * | First of every month at midnight |
| */15 9-17 * * 1-5 | Every 15 min, 9 AM–5 PM weekdays |
| 0 2 * * * | Every day at 2:00 AM |
| 0 8,12,18 * * * | At 8 AM, noon, and 6 PM daily |
Use cases
| Scenario | How this tool helps |
|---|---|
| Server crontab | Verify a crontab schedule before adding it to your server. See the next 50 runs to confirm the pattern. |
| GitHub Actions | GitHub Actions uses standard 5-field cron. Parse your schedule trigger to verify timing. |
| Cloud schedulers | AWS EventBridge, GCP Cloud Scheduler, and Azure use cron. Validate expressions before deploying. |
| CI/CD pipelines | Schedule nightly builds, weekly deploys, or periodic test runs and confirm the timing. |
| Monitoring & alerts | Set up health checks, log rotations, or report jobs and verify they run at the intended times. |
Best practices for cron expressions
- Always verify before deploying — A single digit change can mean "every minute" instead of "once a month." Use this parser to confirm the schedule matches your intent.
- Add comments in your crontab — Put a plain English description above each line (e.g.
# Nightly backup at 2 AM). This parser gives you the wording. - Be careful with day of week — In standard cron, 0 and 7 both mean Sunday. Some systems use 1 = Monday, others 0 = Sunday. Always check.
- Avoid
* * * * *in production — Running a job every minute may overload your system. Use a reasonable interval. - Stagger jobs — Don't schedule everything at minute 0 of the hour. Spread jobs across different minutes to avoid resource spikes.
- Consider timezone differences — Cron runs in the server's timezone. If your team is global, document which timezone the cron is set in.
Common mistakes & how to avoid them
- Confusing minute and hour fields — The first field is minute (0–59), the second is hour (0–23).
9 0 * * *means "at 00:09" (9 minutes past midnight), not "at 9 AM." For 9 AM use0 9 * * *. - Missing the minute field —
* 9 * * *means "every minute during the 9 AM hour" (60 runs). If you want once at 9 AM, use0 9 * * *. - Using 6 or 7 fields — Standard cron uses 5 fields. Some systems add seconds or year, but this parser (and most schedulers including crontab, GitHub Actions) use 5 fields.
- Day of week numbering — 0 = Sunday in most systems.
* * * * 1-5means Monday through Friday. Using1-7may include Sunday twice (7 = Sunday in some implementations). - Combining day-of-month and day-of-week — When both are set (not
*), most cron implementations use OR logic—the job runs on either matching day. This often leads to unexpected extra runs.
FAQ
Does it support 6- or 7-field cron (with seconds)?
This tool supports the standard 5-field format (minute, hour, day of month, month, day of week), which is used by crontab, GitHub Actions, AWS EventBridge, GCP Cloud Scheduler, and most schedulers.
What timezone are next runs shown in?
Next runs are computed and displayed in your browser's local timezone. The current timezone is shown next to the live clock.
Can I use names like MON or JAN?
Currently the parser works with numeric values. Use 1 for Monday and 1 for January. Name-based cron syntax (MON, JAN) is not yet supported.
Does day of week start at 0 or 1?
0 and 7 both represent Sunday. Monday is 1, Saturday is 6. This matches standard POSIX cron behavior.
Is my expression sent to a server?
No. Parsing and next-run computation run entirely in your browser using the cron-parser library. Nothing is sent to any server.
Can I use step values with ranges?
Yes. For example, */15 means every 15 units, and 1-5/2 means every 2nd value in the range 1–5 (i.e. 1, 3, 5).
What is the live clock for?
The live clock shows the current time and timezone so you can immediately see how long until the next scheduled run (shown as a relative countdown like 'in 3m 24s').
Is it free?
Yes. The cron expression parser is completely free with no sign-up required. All processing runs in your browser.
Related terms
This tool is commonly searched as cron parser, cron expression explainer, cron job tester, crontab guru, cron schedule checker, cron next run, parse cron expression online, cron syntax validator, cron to human readable, and cron expression generator. It helps you verify cron schedules used in crontab, GitHub Actions, CI/CD pipelines, and cloud schedulers—all without leaving the browser.
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Conclusion
A cron expression parser is an essential tool for anyone scheduling jobs on servers, CI/CD pipelines, or cloud platforms. This tool parses any 5-field expression into plain English, shows the next run times in your timezone, provides presets and real-world examples, and includes a syntax reference—all in the browser with no sign-up. Verify your cron schedule before deploying and share the explanation with your team.