Leap Year Tools
Explore our collection of tools for working with leap years in your applications. These tools demonstrate the capabilities of our API and provide useful functionality for developers and users alike.
Leap Year Calculator
Check if any year is a leap year using our simple calculator. Just enter a year between 1582 (when the Gregorian calendar was introduced) and 9999 to get an instant result.
Leap Year Calendar
Visualize leap years across decades with our interactive calendar. Green cells indicate leap years, and you can navigate between decades to explore patterns.
Batch Leap Year Testing
Need to check multiple years at once? Our batch tester lets you process up to 100 years simultaneously, perfect for data analysis or historical research.
Leap Year Facts
Did you know?
- •2025 is not a leap year in the Gregorian calendar.
- •The next leap year after 2025 is 2028, which is 3 years later.
- •The Gregorian calendar has 97 leap years every 400 years, which averages to a 365.2425-day year.
- •The actual length of the astronomical year is approximately 365.2422 days, which means the Gregorian calendar's leap year rule is off by about 1 day every 3,236 years.
- •People born on February 29 are sometimes called "leaplings" or "leap year babies."
Developer Code Snippets
JavaScript
JavaScript Leap Year Function
function isLeapYear(year) {
return ((year % 4 === 0) && (year % 100 !== 0)) || (year % 400 === 0);
}TypeScript
TypeScript Leap Year Function
function isLeapYear(year: number): boolean {
return ((year % 4 === 0) && (year % 100 !== 0)) || (year % 400 === 0);
}Using Our API
Fetch API Example
// Check if 2024 is a leap year
fetch('https://isleapyear.app/api/check/2024')
.then(response => response.json())
.then(data => {
console.log(`Is 2024 a leap year? ${data.isLeapYear}`);
console.log(`Days in February: ${data.daysInFebruary}`);
console.log(`Next leap year: ${data.nextLeapYear}`);
})
.catch(error => console.error('Error:', error));