Cron Diff
Expressions are identical.
| Field | A | B |
|---|---|---|
| Minute | 0 | 0 |
| Hour | 9 | 9 |
| Day of month | * | * |
| Month | * | * |
| Weekday | 1-5 | 1-5 |
Human (A)
At 09:00, on Monday, Tuesday, Wednesday, Thursday, Friday.
Human (B)
At 09:00, on Monday, Tuesday, Wednesday, Thursday, Friday.
How to use
- Paste the original cron expression in side A and the new one in side B.
- Read the field-by-field table to see which of the five fields changed.
- Compare the plain-English summary for each side to confirm the change does what you intended.
FAQ
What does a cron diff show?
It compares two cron expressions field by field — minute, hour, day, month, weekday — and highlights which fields differ, with a plain-English meaning for each side.
When should I use a cron diff?
During code review or migration, when a pull request changes a schedule and you need to confirm the new timing matches intent before merging.
Is my data sent anywhere?
No. The comparison happens locally in your browser.
Introduction
A cron diff makes a schedule change reviewable. In a pull request, a one-character edit to a cron line is easy to miss and hard to reason about. Comparing the two expressions side by side — with a plain-English translation of each — turns "the cron changed" into "it now runs hourly instead of every 15 minutes."
Example comparison
| Field | A (*/15 * * * *) |
B (0 * * * *) |
Changed |
|---|---|---|---|
| Minute | */15 |
0 |
Yes |
| Hour | * |
* |
— |
| Day | * |
* |
— |
| Month | * |
* |
— |
| Weekday | * |
* |
— |
Plain English: A runs "every 15 minutes," B runs "at minute 0 of every hour." The diff makes the impact obvious — 4x fewer runs.
Why field-by-field matters
A raw text diff just shows characters changed. A field-aware diff tells you which dimension of the schedule moved — frequency, time of day, or day of week — which is what actually matters when approving the change.
Common Use Cases
- Reviewing a scheduling change in a pull request before merging.
- Confirming a migration kept the intended cadence across environments.
- Documenting before/after timing in a change ticket.
Best Practices
- Normalize spacing before comparing so whitespace noise does not hide real changes.
- Confirm each side independently with cron to human readable.
- After approving, preview the new run times with the cron next run calculator.