Cron Load Analyzer
Analyze cron expression load: calculate executions per hour/day/month, detect excessive frequency and simultaneous executions
Standard 5-field cron format: minute (0-59), hour (0-23), day of month (1-31), month (1-12), day of week (0-7).
What is the Cron Load Analyzer?
The Cron Load Analyzer evaluates one or more cron expressions and calculates their combined execution frequency. It reports how many times your cron jobs will fire per hour, day, and month, detects excessive scheduling that could overwhelm system resources, and identifies simultaneous executions (collisions) when multiple crons overlap.
How to Use
- Enter one or more cron expressions, each on its own line
- The analysis runs automatically as you type
- Review the summary for total execution counts
- Check alerts for excessive frequency warnings
- Review collisions to find overlapping schedules
Use Cases
- Server capacity planning — Calculate total scheduled load before deploying new cron jobs
- Collision avoidance — Detect when multiple jobs fire at the same time, competing for resources
- Frequency auditing — Identify overly aggressive schedules that run every second or every minute
- Crontab review — Paste your entire crontab to get a bird's-eye view of scheduling load
- Cost estimation — Calculate monthly execution counts for cloud functions billed per invocation
Example: Analyzing a Production Crontab
Given a typical set of production cron jobs:
# Health check - every 5 minutes
*/5 * * * *
# Report generation - weekdays at 9 AM
0 9 * * 1-5
# Database backup - daily at 2:30 AM
30 2 * * *
# Cache cleanup - every 2 hours
0 */2 * * *The analyzer reports combined load: approximately 300 executions/day, flags the health check as the highest-frequency job (12/hour), and checks for any timing overlaps between jobs.
Understanding Cron Fields
- Field 1 — Minute: 0-59, when in the hour the job runs
- Field 2 — Hour: 0-23, which hour(s) the job runs
- Field 3 — Day of Month: 1-31, which day(s) of the month
- Field 4 — Month: 1-12, which month(s)
- Field 5 — Day of Week: 0-7 (0 and 7 are Sunday)
Alert Thresholds
The analyzer flags these conditions:
- Critical: A single expression fires 60+ times/hour (every minute or more)
- Critical: Combined load exceeds 100 executions/hour across all expressions
- Warning: A single expression fires 1440+ times/day
- Warning: Combined load exceeds 2000 executions/day
Privacy and Security
All analysis happens entirely in your browser using JavaScript. Your cron expressions are never transmitted to any server. No data is stored, logged, or shared.
Frequently Asked Questions
What does the Cron Load Analyzer do?
The Cron Load Analyzer evaluates one or more cron expressions and calculates their execution frequency per hour, day, and month. It detects excessive scheduling, identifies simultaneous executions across multiple crons, and shows the next upcoming execution times.
How do I analyze multiple cron expressions?
Enter each cron expression on a separate line. The tool will analyze each one individually and also check for scheduling conflicts (simultaneous executions) between them. Lines starting with # are treated as comments and ignored.
What counts as excessive frequency?
A single expression that fires 60 or more times per hour (essentially every minute or more) is flagged as critical. Combined load exceeding 100 executions per hour across all expressions is also flagged. These thresholds help identify schedules that may overwhelm system resources.
What are simultaneous executions?
When two or more cron expressions are scheduled to fire at the exact same time, they create a simultaneous execution (collision). This can cause resource contention — for example, multiple batch jobs competing for CPU or database connections at the same instant.
What cron format is supported?
Standard 5-field cron format: minute (0-59), hour (0-23), day of month (1-31), month (1-12), day of week (0-7, where both 0 and 7 represent Sunday). Supports wildcards (*), ranges (1-5), lists (1,3,5), and step values (*/5).
How far ahead does it calculate next executions?
The tool calculates up to 10 next execution times, searching up to 30 days ahead. Collision detection looks within the next 24 hours from the current time.
Is my data sent to a server?
No. All analysis happens entirely in your browser. Your cron expressions never leave your device. No data is stored, logged, or transmitted.