Cron Expression Parser

Parse and explain 5-field Unix and 6-field Extended cron expressions into plain English sentences. Calculates upcoming next execution timestamps to verify schedule accuracy.

Why Use This Tool?

• Audit Server Cron Jobs: Decode mysterious existing crontab expressions from production servers into clear English descriptions.
• Verify Execution Schedule: View exact future execution timestamps (Next 5 run times) before saving cron scripts.
• Syntax Validation: Detect invalid field ranges, illegal characters, and syntax errors.

How to Use

1. Paste any cron expression (e.g. `*/10 9-17 * * 1-5`).
2. The parser translates the schedule into plain English in real time.
3. View upcoming next 5 execution dates and times.

Real Working Example

Input:

Cron Expression: 0 0 1,15 * *

Output Result:

Schedule Description: "At 12:00 AM, on day 1 and 15 of the month"
Next Run Times:
1. Sep 1, 2026 00:00:00
2. Sep 15, 2026 00:00:00
3. Oct 1, 2026 00:00:00

Important Technical Details & Specifications

• cronstrue & cron-parser Engine: Uses `cronstrue` for multi-language natural English translation and `cron-parser` for execution date math.
• 5 & 6 Field Support: Parses standard 5-field (Min, Hour, Day, Month, DoW) and 6-field (including Seconds) expressions.
• Local Memory Execution: Fast local evaluation in browser memory.

Related Developer Tools

• Crontab Generator: Build crontab expressions interactively.
• Unix Timestamp Converter: Convert epoch timestamps.
• Date Difference Calculator: Calculate date durations.