What is the difference between 5-field and 6-field cron expressions?

Standard Unix/Linux crontab uses 5 fields (Minute, Hour, Day of Month, Month, Day of Week). Quartz, AWS EventBridge, and Spring often support a 6th field for Seconds (at the beginning) or Year (at the end). Our tool clearly validates standard 5-field expressions.

How do step values like */15 work in cron syntax?

The slash '/' operator specifies increments. For instance, '*/15' in the minute field means 'every 15 minutes starting from minute 0' (i.e., at minutes 0, 15, 30, and 45).

Is Sunday represented by 0 or 7 in cron?

Most modern Unix implementations (like Vixie cron) accept both 0 and 7 as Sunday. In this tool, standard 0-6 notation is supported where 0 = Sunday, 1 = Monday, ..., 6 = Saturday.

Cron Expression Parser & Visual Builder

Translate crontab schedules into plain English, inspect upcoming execution timelines, and visually configure recurring cron jobs in real time.

Cron Expression (5-part Unix syntax)

Valid Expression

Human-Readable Schedule Description

“Every 15 minutes, between 09:00 AM and 05:59 PM, Monday through Friday”

Minute*/150 - 59

Hour9-170 - 23

Day of Month*1 - 31

Month*1 - 12

Day of Week1-50 - 6 (Sun-Sat)

Interactive Field Builder (Quick Select)

Minute (1st):

Hour (2nd):

Day of Month (3rd):

Month (4th):

Day of Week (5th):

Upcoming 5 Trigger Times (Local Timezone)

Calculated dynamically against your local system clock and timezone offsets:

1Mon, Sep 28, 2026, 09:00:00 AM GMT+8

in 2 days

2Mon, Sep 28, 2026, 09:15:00 AM GMT+8

in 2 days

3Mon, Sep 28, 2026, 09:30:00 AM GMT+8

in 2 days

4Mon, Sep 28, 2026, 09:45:00 AM GMT+8

in 2 days

5Mon, Sep 28, 2026, 10:00:00 AM GMT+8

in 2 days

Frequently Used Schedule Presets

Cron Operator Quick Reference

* (Asterisk)

Matches any value in the field (e.g. every minute, every hour).

, (Comma)

Specifies discrete value lists (e.g. 1,15,30).

- (Hyphen)

Specifies inclusive ranges (e.g. 1-5 for Mon through Fri).

/ (Slash)

Specifies step increments (e.g. */15 for every 15 minutes).

How Cron Expression Parser & Visual Builder Works & Technical Principles

Deconstruct, generate, and predict cron schedule execution times directly in your browser with zero latency. Supports standard Unix 5-part expressions, step intervals, and common presets.

Technical Overview: Time-Based Job Scheduling & Field Masking

Cron expressions represent recurring schedules through positional space-separated fields (minute, hour, day-of-month, month, day-of-week). Parsers evaluate these fields against system time using bitmasks and modulo step operations to compute deterministic trigger boundaries.

How It Works

STEP 01

Enter or Build Expression

Type a cron expression directly, choose from quick presets, or use the interactive visual builder to configure minutes, hours, and days.

Input & Configuration

STEP 02

Real-Time Translation

The parser translates the cron string into an unambiguous, human-readable English description (e.g., 'At 09:00 AM on weekdays').

Client-Side Processing

STEP 03

Timeline & Verification

Inspect the exact next 5 upcoming trigger dates and times in your local timezone and copy the validated expression.

Instant Output

Key Capabilities & Features

Plain-English Schedule Translation

Instant translation of complex cron syntax into human-friendly explanations without cryptic symbols.

Upcoming Execution Timelines

Calculates the exact next 5 trigger times with countdowns and local timezone adaptation.

Visual Interactive Builder

Pick intervals, specific hours, days of the week, or months with clean point-and-click controls.

Extensive Preset Library

Quick-load popular schedules for hourly backups, daily reports, midnight syncs, and weekday cron jobs.

Technical Standards & RFC Specifications

IEEE Std 1003.1 (POSIX)

Standard crontab format and crontab utility specifications

Vixie Cron Standard

Extended cron schedule syntax supporting step operators (/) and named days/months

Frequently Asked Questions

Privacy Guarantee: All computations execute locally within your browser sandbox. No source data, tokens, or files are ever transmitted to any remote server.

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