Add Errors to Calendar Dates

The Add Errors to Calendar Dates Tool takes valid dates and introduces random formatting or logical errors for testing and simulation. You can apply digit swaps, insert random character noise, inject invalid day/month values, and truncate or duplicate date parts. Ideal for testing how systems handle bad date inputs, this tool updates live and includes export and copy options.

With a simple toggle interface and real-time results, the Add Errors to Calendar Dates Tool is perfect for QA, data validation, and parser stress testing.

Paste your input above or import a file below.
No file chosen
Supported file types: .txt, .csv, .log, .json, .xml, .md, .ini, .yaml, .yml, .html, .htm, .css
Total items: 0
Options
Swap digits
Add noise
Inject invalid day/month
Truncate/duplicate
Shuffle output
Max Dates:

How to Use:

  1. Paste valid dates into the Input Calendar Dates box (e.g. YYYY-MM-DD, one per line).
  2. Use the Options toggles to apply:
    • Swap digits: flip day/month digits
    • Add noise: insert random corruption like ??, XX, etc.
    • Inject invalid day/month: force values like 35 or 14
    • Truncate/duplicate: shorten or repeat parts of the date
    • Shuffle output: randomize the result order
  3. Click Add Errors to instantly see corrupted output.
  4. Use Copy Output or Export to File to save the result.
  5. Click Clear All to reset both boxes.

What Add Errors to Calendar Dates Tool can do:

This tool helps you generate syntactically malformed or semantically invalid dates from valid input. You can:

  • Apply multiple types of corruption simultaneously
  • Instantly see the effects in a preview window
  • Shuffle for randomness or sequence unpredictability

It’s a flexible utility for creating realistic edge cases.

Example:

Input:
2024-01-01
2024-03-15
2024-07-30

Output:
2024-01-13
2024-XX-??
2024-03-5
202-07-30
ZZZZ-??-12

Common Use Cases:

This tool is essential for:

  • Testing how parsers handle malformed or corrupted dates
  • Validating error handling and logging
  • Generating data for negative test cases
  • Simulating real-world bad input from users or imports

QA teams, developers, and data engineers can all use this tool to build more resilient systems.

Useful Tools & Suggestions:

If you’re experimenting with randomness, Generate Invalid Calendar Dates can help you test edge cases. Or try Add Fuzziness to Calendar Dates when you want to soften the precision without totally breaking structure.

Related Tools