Developing calendar-exact age calculation algorithms in software requires handling UTC timezones, month day boundaries (28–31 days), and leap year edge cases.
Production JavaScript Implementation
function calculateExactAge(dob, asOf) {
let years = asOf.getFullYear() - dob.getFullYear();
let months = asOf.getMonth() - dob.getMonth();
let days = asOf.getDate() - dob.getDate();
if (days < 0) {
months--;
const prevMonthDays = new Date(asOf.getFullYear(), asOf.getMonth(), 0).getDate();
days += prevMonthDays;
}
if (months < 0) {
years--;
months += 12;
}
return { years, months, days };
}
Experience our optimized production implementation live at AgeCalculate.net.