Check If a Year Is a Leap Year

Need to know if a year is not a leap year? The Check If a Year Is a Common Year Tool helps you identify whether each year you enter is a common year or a leap year. It accepts multiple years at once, handles invalid input, and updates results live as you type or import a file.

You’ll get clear output showing which years are regular (365-day) years and which are leap years.

Paste your input above or import a file below.
No file chosen
Supported file types: .txt, .csv, .log
Total lines: 0

How to Use:

  1. Enter one year per line in the Input Year(s) box.
  2. Or click Choose File to import a .txt, .csv, or .log file with year values.
  3. The Result box will label each entry as:
    • common year not a leap year
    • leap year follows leap year rules
    • invalid if the entry is not a valid number
  4. Use Copy Output to copy the results or Export to File to download them.
  5. Click Clear All to reset the input and results.

What Check If a Year Is a Common Year Tool can do:

  • Analyzes each line to determine leap vs common year
  • Highlights invalid or non-numeric entries
  • Accepts both typed and file-based input
  • Updates output live and shows total lines processed
  • Includes copy and export functionality

Example:

Input:

1999
2000
1900
2023
2024
abc

Output:

1999 = common year  
2000 = leap year  
1900 = common year  
2023 = common year  
2024 = leap year  
abc = invalid

Common Use Cases:

This tool is ideal for developers validating date logic, teachers demonstrating calendar rules, or anyone handling date-based datasets. It quickly flags leap years and non-leap years without any math or lookups.

Useful Tools & Suggestions:

If you’re checking year types, Check If a Year Is a Leap Year is the natural pair to confirm what’s what. And to explore trends, Find Common Years shows a full list you can scan through quickly.

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