Age Calculator
Find your exact age in years, months, days, and ticking seconds from your birth date.
This runs entirely in your browser. Your birth date is never uploaded anywhere.
How to use this tool
Pick your date of birth using the first field. The calculator instantly shows your exact age as years, months, and days, then breaks the same span down into total months, weeks, days, hours, minutes, and seconds. The "Age as of" field is optional: leave it blank to measure your age right now, or set a specific date to answer questions like "how old will I be on a future date" or "how old was I on a past date". Press Calculate age to refresh, and use Copy result to grab a clean summary you can paste anywhere.
How it works
total_minutes = total_seconds / 60
total_hours = total_minutes / 60
total_days = total_hours / 24
years/months/days = calendar difference, borrowing days and months as needed
The exact age in years, months, and days is found by subtracting the birth year, month, and day from the target date and "borrowing" when a value goes negative, the same way you borrow when subtracting numbers by hand. The total figures (days, hours, minutes, seconds) come from a single subtraction of the two timestamps in milliseconds, so they are always accurate to the current moment. Your browser's own clock supplies the current time, which is why the seconds tick forward live.
A real example
Suppose someone was born on January 15, 1990, and we check their age on June 3, 2026. The calendar difference is 36 years, 4 months, and 19 days. In raw units that is roughly 13,288 total days, which is about 318,912 hours, 19,134,720 minutes, and more than 1.14 billion seconds. The seconds value keeps climbing by one every second the page stays open, so the number you copy is a true snapshot of that instant.
Common questions
How does the age in seconds calculator stay accurate?
It reads your computer or phone clock once per second and subtracts your birth date from the current time in milliseconds. Because it uses the live system clock, the seconds count is exact to the moment you read it, as long as your device time is correct.
Can I find my exact age on a future birthday?
Yes. Put your date of birth in the first field and the future date in the "Age as of" field. The tool will show how old you will be on that day, including the years, months, days, and the total minutes and seconds up to that point.
Why does the months and days breakdown differ from a simple subtraction?
Months have different lengths, so the tool borrows days from the previous month and months from the year when a value would go negative. This gives the natural "X years, Y months, Z days" answer instead of an awkward fraction.
How old am I if I only know my birth year?
This calculator needs a full date for an exact result. If you only know the year, pick January 1 of that year for an approximate age, then adjust once you confirm the real birthday.
Is my birth date sent to a server?
No. Everything is calculated locally in your browser using JavaScript. Nothing is uploaded, stored online, or shared, so the tool works even if you go offline after loading the page.