Build cron expressions visually — set each field with a click and get an instant plain-English preview of when your job runs.
| Symbol | Meaning | Example | Reads as |
|---|---|---|---|
* | Any / every value | * * * * * | Every minute |
, | List of values | 0,30 * * * * | At minute 0 and 30 |
- | Range of values | 0 9-17 * * * | Every hour from 9 AM to 5 PM |
/ | Step / interval | */10 * * * * | Every 10 minutes |
1-5 | Weekday range | 0 8 * * 1-5 | 8 AM, Monday–Friday |
| Field | Position | Allowed Values | Special Names |
|---|---|---|---|
| Minute | 1st | 0–59 | — |
| Hour | 2nd | 0–23 | — |
| Day of Month | 3rd | 1–31 | — |
| Month | 4th | 1–12 | JAN–DEC |
| Day of Week | 5th | 0–7 (0 & 7 = Sun) | SUN MON TUE WED THU FRI SAT |
Building a cron expression from scratch means remembering five fields, each with their own syntax quirks — and one typo means your scheduled job never runs. The Cron Expression Builder lets you set minute, hour, day-of-month, month, and day-of-week using simple dropdowns and inputs, then instantly shows you the resulting expression and a plain-English description of when it runs. No manual syntax guessing required.
How to Build a Cron Expression
- Set the minute field — Choose a specific minute, a step interval (e.g., every 5 minutes), or leave it as
*for every minute. - Set the hour field — Pick specific hours (0–23) or use ranges and intervals to define when your job runs during the day.
- Set the day-of-month field — Choose specific dates (1–31) or leave as
*to run on every day. - Set the month and day-of-week fields — Narrow your schedule by month or weekday for precise control.
- Copy your expression — The final cron string updates in real time as you adjust each field. Click "Copy" and paste it into your crontab, CI config, or scheduler.
Why Use Flipper File to Build Cron Expressions?
- Visual interface, zero syntax memorization — Click to select values for each field instead of writing raw cron syntax by hand.
- Instant human-readable preview — See a plain-English description like "Every 15 minutes, Monday through Friday" update in real time as you build.
- Common schedule presets — Jump-start your expression with one-click presets like "Every hour," "Daily at midnight," "Every weekday," and more.
- Full cron expression support — Handles
*,,,-, and/operators across all five standard fields. - Reverse lookup / import — Paste an existing cron expression to decode and edit it visually.
- 100% free, no login, no tracking — Runs entirely in your browser; nothing is sent to any server.
Frequently Asked Questions
What is a cron expression?
A cron expression is a string of five fields (minute, hour, day-of-month, month, day-of-week) separated by spaces that tells a Unix/Linux scheduler (cron daemon) when to run a command or script. For example, 0 9 * * 1 means "every Monday at 9:00 AM."
What do the five cron fields represent?
Reading left to right: (1) Minute (0–59), (2) Hour (0–23), (3) Day of month (1–31), (4) Month (1–12 or JAN–DEC), (5) Day of week (0–7, where 0 and 7 both mean Sunday). Each field supports * (any), , (list), - (range), and / (step) operators.
What does */5 mean in a cron expression?
The / character sets a step interval. */5 in the minute field means "every 5 minutes." */2 in the hour field means "every 2 hours." It's shorthand for listing every nth value across the full range.
Can I schedule a job to run multiple times per hour?
Yes. Use a comma-separated list in the minute field (e.g., 0,15,30,45 * * * * for every 15 minutes) or a step interval (e.g., */15 * * * *). Both produce the same result.
Is there a 6-field cron format with seconds?
Some schedulers (like Quartz in Java, or AWS EventBridge) use a 6-field format that adds a seconds field. Standard Unix cron only uses 5 fields. This tool targets the standard 5-field format used by crontab, GitHub Actions schedules, and most Linux-based schedulers.
What's the difference between day-of-month and day-of-week?
Day-of-month (field 3) refers to the numeric date (e.g., the 15th of every month). Day-of-week (field 5) refers to the day name (e.g., every Monday). When both are specified, most implementations use OR logic — the job runs if either condition is met.
How do I run a cron job only on weekdays?
Set day-of-week to 1-5 (Monday through Friday). A full expression for every weekday at 8 AM would be 0 8 * * 1-5.
What's the difference between this tool and your Crontab to Human Readable converter?
The Crontab to Human Readable Converter goes one direction — you paste an existing cron expression and get a plain-English description. This Cron Expression Builder goes the other direction — you describe your schedule visually and it generates the cron expression for you. Use both together for a complete workflow.