Say Goodbye to Leap Year Confusion, Forever.
Every four years, millions of developers face the same crisis: broken date calculations due to leap years.
days = 28;
}
The API Endpoint
GET "https://isleapyear.app/api/check"{
"isLeapYear": false,
"daysInFebruary": 28,
"nextLeapYear": 2028,
"yearChecked": 2025,
}Implementation Example
// Using fetch API
fetch('https://isleapyear.app/api/check')
.then(response => response.json())
.then(data => {
if (data.isLeapYear) {
februaryDays.textContent = "29 days this month!";
} else {
februaryDays.textContent = "28 boring days";
}
});Features
Quantum-Powered
Our proprietary Quantum LeapCore™ Engine consults astronomical data and calculates leap years with 99.9999% accuracy.
Ultra Secure
Military-grade encryption ensures your leap year status remains confidential from competitors.
Hyper Scalable
Built on top of serverless technology to handle billions of leap year checks per second.
Multi-Calendar Support
Supports Gregorian, Julian, Hebrew, and Mayan calendar systems for truly global applications.
Detailed Analytics
Track your leap year API usage across all your applications with our comprehensive dashboard.
ROI Guaranteed
Our enterprise customers report a 400% ROI from preventing leap year-related disasters.
Understanding Leap Years: A Historical Perspective
The History of Leap Years
Ancient Origins
The concept of leap years dates back to ancient Egypt. Around 238 BCE, Ptolemy III Euergetes tried to add an extra day every four years. However, the Egyptian priests resisted this change, and it wasn't widely implemented.
Julian Calendar
In 45 BCE, Julius Caesar implemented the Julian calendar with the help of the astronomer Sosigenes. This calendar introduced a leap day every four years without exception, which was an improvement but still not perfect.
Gregorian Reform
By the 16th century, the Julian calendar had drifted about 10 days from the solar year. In 1582, Pope Gregory XIII introduced the Gregorian calendar, which we still use today. It refined the leap year rule: years divisible by 4 are leap years, except for century years (divisible by 100) which must also be divisible by 400 to be leap years.
Adoption Timeline
The Gregorian calendar wasn't adopted simultaneously worldwide. Catholic countries adopted it first in 1582. Protestant regions followed later, with Great Britain and its colonies (including what would become the United States) not adopting it until 1752. Some countries didn't adopt it until the 20th century — Russia in 1918 and Greece in 1923.
Modern Accuracy
The Gregorian calendar's leap year system creates a mean year of 365.2425 days, which is very close to the actual solar year of approximately 365.2422 days. This means it will take about 3,300 years before the Gregorian calendar is off by a full day.
Fun Leap Year Facts
- Leap year babies (born on February 29) are sometimes called "leaplings"
- The Olympic Games and US Presidential elections occur in leap years
- According to Irish tradition, women can propose to men on leap day
- The chance of being born on February 29 is about 1 in 1,461
- People born on leap day celebrate their birthdays on either February 28 or March 1 in non-leap years
The Actual Solution
Of course, all of this is completely unnecessary. Here's how you actually check for a leap year:
function isLeapYear(year) {
return ((year % 4 === 0) && (year % 100 !== 0)) || (year % 400 === 0);
}
// Usage
console.log(isLeapYear(2024)); // true
console.log(isLeapYear(2025)); // false
console.log(isLeapYear(2100)); // false (century year)But where's the fun in that? Our engineers needed something to do!