What does * mean in cron?

An asterisk means "every possible value" for that field — it matches unconditionally. "* * * * *" means the job runs every single minute, of every hour, of every day.

What is the difference between "*/4" and a fixed hour like "4" in the hour field?

"*/4" in the hour field means "every 4 hours" — so it matches hours 0, 4, 8, 12, 16, and 20. A fixed "4" matches only the single hour 4 (4 AM). Confusing these two is one of the most common cron mistakes.

What is the difference between cron and crontab?

A "cron job" is any individual scheduled task. "Crontab" (cron table) is the file — and the command used to edit it — where a user's list of cron jobs is stored on a Unix-like system. You run "crontab -e" to edit your own schedule.

Do cron expressions support seconds?

Standard Unix cron uses exactly 5 fields with no seconds field — the finest granularity is one minute. Some job schedulers, including Spring, Quartz, and AWS CloudWatch Events, extend the syntax with an optional 6th field for seconds. This tool parses standard 5-field cron.

What happens if I put an invalid value in a field, like 60 in the minute field?

Behavior varies by cron implementation — some silently clamp or ignore the job, others log an error and skip it, and some Unix cron daemons refuse to load the crontab at all until it is fixed. Because this is inconsistent across systems, always keep field values within their valid range (0-59 for minutes, 0-23 for hours, and so on).

Why does my job run twice a day when I only expect once?

This usually happens when both the day-of-month and day-of-week fields are set to something other than "*". Most cron implementations treat these two fields as OR'd together rather than AND'd, so "0 0 1,15 * 1" runs at midnight on the 1st, the 15th, AND every Monday — not just when both conditions are true simultaneously.

What timezone are the next-run-time calculations based on?

The calculations use your browser's local system time and timezone. If your actual cron daemon or scheduler runs in UTC or a different server timezone, adjust the hour field accordingly or convert the displayed times using the Convert Timestamp tool before deploying the schedule.

Can I test a 6-field expression with a seconds field here?

This tool is built for the standard 5-field format used by Unix cron, most CI/CD schedulers, and Kubernetes CronJobs. If your system uses a 6-field format with seconds, drop the leading seconds field before pasting, verify the remaining 5 fields, then add the seconds value back for your target system.

All ToolsParse Cron Expression

Parse Cron Expression

Translate cron expressions to plain English and see the next 5 scheduled execution times.

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What is Parse Cron Expression?

Parse Cron Expression is a free online tool that translates standard 5-field cron syntax into a plain-English schedule description and computes the next several execution times from right now. Paste an expression like "0 9 * * 1-5" and instead of mentally decoding five cryptic fields, you get "runs at 09:00 on Monday through Friday" plus a concrete list of upcoming run timestamps.

Cron itself dates back to Unix in 1975 and the syntax has barely changed since — five whitespace-separated fields representing minute (0–59), hour (0–23), day of month (1–31), month (1–12), and day of week (0–6, where 0 is Sunday), each of which can hold a literal number, an asterisk for "any value," a step value using a slash, a range using a hyphen, or a comma-separated list. That compactness is exactly why cron expressions are so easy to misread: "0 */4 * * 1-5" and "0 4 * * 1-5" look almost identical on screen but mean completely different things — one runs every four hours on weekdays, the other runs exactly once at 4 AM on weekdays. A single misplaced character silently changes a nightly backup into an hourly one, or a weekday-only report into a job that also fires on weekends. Because cron jobs typically run unattended and their output rarely gets watched in real time, a wrong schedule can go unnoticed for weeks.

This tool exists for the moment right before you commit a crontab entry, a Kubernetes CronJob spec, a GitHub Actions "on: schedule" block, or an AWS CloudWatch Events rule — the moment you want a second opinion on what an expression actually does before it goes live. It also works in reverse for debugging: paste in a schedule pulled from an existing server, CI pipeline, or a coworker's pull request, and get an immediate human-readable translation plus the next handful of run times so you can verify the behavior matches what the job is supposed to do, without waiting around for it to actually fire.

All parsing and time computation happens in your browser using ordinary date arithmetic — the tool steps forward minute by minute from the current time, checking each of the five fields against the candidate date until it finds matches, and stops once it has collected enough upcoming run times. There is no server call and no data transmitted, so it is safe to paste in schedules from internal or private infrastructure.

How It Works

The parser splits the cron expression on whitespace into its five fields and applies plain-English translation rules to each: an asterisk becomes "every," a slash value becomes "every N," a hyphenated range becomes "N through M," and a comma-separated list is spelled out directly. Weekday and month numbers are mapped to their names (0 = Sunday, 1 = January, and so on) rather than left as raw digits. To compute upcoming run times, the tool starts at the next full minute after the current time and steps forward one minute at a time, testing all five fields against each candidate timestamp, until it has collected five matching future times — this brute-force minute-stepping approach is simple and always correct, even for unusual combinations of step values and ranges that trip up more clever shortcut algorithms.

How to Use

1
Enter a cron expression
Type or paste a 5-field cron expression (e.g. "0 9 * * 1-5") into the input field.
2
Or start from a preset
Click a common preset like "Every weekday at 9am" or "Daily at midnight" to load a working expression you can then customize.
3
Parse the expression
Click "Parse Expression" to see the plain-English translation, such as "Runs at 09:00, on Monday through Friday."
4
Review the field breakdown
Check the individual description for each of the 5 fields — minute, hour, day of month, month, and day of week — to confirm each one matches your intent.
5
Check the next 5 run times
Scan the computed list of upcoming execution timestamps to verify the schedule fires exactly when you expect, especially around edge cases like month boundaries.
6
Copy into your crontab or scheduler
Once verified, paste the expression into your crontab, CI/CD YAML file, Kubernetes CronJob spec, or cloud scheduler rule.

Who Uses This Tool

⏰

Scheduled Job Debugging

Paste a cron expression from a failing CI/CD pipeline or server crontab to instantly see when it runs next.

🔄

Backup Schedule Verification

Confirm that a database or file backup cron runs at the correct frequency and time before going to production.

📧

Email Digest Scheduling

Build and test cron expressions for automated email reports to ensure they fire at the expected business times.

🌍

Cross-Timezone Planning

Check next run times to mentally convert scheduled jobs between UTC and local time zones.

🧪

CI Pipeline Scheduling

Verify GitHub Actions or GitLab CI scheduled workflow expressions before committing them to your repository.

📚

Learning Cron Syntax

Use the plain-English translation and field breakdown to understand how each part of a cron expression works.

Why Choose This Tool

Plain English Translation

Every cron expression is converted to a readable description like "Every weekday at 9:00 AM" for instant comprehension.

Next 5 Run Times

Computes the next 5 scheduled execution times from right now so you can verify timing without waiting.

Field-by-Field Breakdown

Displays each of the 5 cron fields with its individual description to help you understand complex expressions.

Common Presets

One-click preset buttons for everyday schedules let you start from a working example and customize from there.

Special Character Support

Handles *, /, -, and , operators in all fields so step values, ranges, and lists are all correctly parsed.

Browser-Based

No installation or sign-up required — parse any cron expression instantly in the browser.

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Key Benefits

Translates any standard 5-field cron expression into plain English
Computes the next 5 scheduled execution times from right now
Field-by-field breakdown showing what each of the 5 positions means
One-click presets for the most common scheduling patterns
Correctly handles *, step (/), range (-), and list (,) syntax in every field
100% browser-based — safe to paste schedules from private infrastructure
No installation, account, or crontab access required to test an expression
Useful for both writing new schedules and auditing existing ones

Frequently Asked Questions

Also Known As

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