Does the life clock account for leap years?

Yes. The day count includes every February 29 that has occurred since your birth. The Gregorian calendar rules (year divisible by 4, except centuries not divisible by 400) are built into the calculation.

Why does the hours number change during the day?

Hours are calculated from your exact birth time to the current moment. Each hour that passes adds one to the counter. Check at 8:00 AM and again at 4:00 PM, and the hours number will be eight higher the second time.

What happens if I don't know my birth time?

The clock defaults to 12:00 PM (noon) on your birth date. The years, days, and weeks counters will be correct regardless. The hours and seconds counters will be approximate, off by up to 12 hours.

Can I use this for someone else, like a child or elderly parent?

Yes. Enter their birth date and time, and set the lifespan assumption to whatever figure is appropriate for their country and sex. The clock displays their elapsed proportion, not yours.

Why does the bar look different when I change the lifespan assumption?

Because the filled portion is a ratio of time elapsed to total assumed time. A longer assumed lifespan means the same elapsed time represents a smaller proportion. The bar shrinks the filled portion as the denominator grows.

Life Clock

A life clock answers one question: If I live exactly to this age, how much of that time have I already used? It does not predict a death date. It shows a proportion. The number driving that proportion is a statistical average drawn from a population, not a prophecy for an individual.

Proportion of life elapsed

The life clock takes your exact age, down to the second you were born, and divides it by a life expectancy you choose. The result is a percentage. If you are 40 years old and your assumed lifespan is 80 years, the clock shows 50% of that time has passed. Half remains.

This is a ratio. The answer changes the moment you adjust the life expectancy number, because the denominator changes.

How the default life expectancy is set

The default is 80 years. That is a round, memorable figure, roughly the global average for a person born in the early 2000s, but it is almost certainly not your number. Life expectancy at birth varies by country by more than 20 years. A woman in Japan born in 2026 has a different statistical outlook than a man in Nigeria born the same year.

Change the default. Use the most recent figure from your own country's statistical agency or the World Health Organization. In the United Kingdom, use the Office for National Statistics figure. In the United States, use the CDC's National Center for Health Statistics number. The Life Expectancy by Country: Global Comparison Table gives a starting point, but national agencies publish the most current data.

Do not use 80 years just because it is the default. That defeats the purpose.

What the years, days, hours and seconds count

Below the main display four counters tick. They show how much time has passed since your birth, not how much remains.

Years are the simplest: completed calendar years since your birth date. If you were born on 15 June 1990 and today is 1 October 2026, the years counter shows 36. You have lived 36 full years. The fraction of the current year (June to October) does not appear here; it shows up in the other units.

Days count every calendar day from your birth date to today. This number respects leap years. 2024 had an extra day, 2025 did not. Over 80 years, ignoring leap days would undercount by about 20 days. The How Age Calculators Handle Leap Years article explains the mechanics.

Hours multiply the day count by 24, then add the hours elapsed since midnight on your birthday. If you were born at 3:00 PM and it is now 9:00 PM on your birthday, the hours counter shows 6 for that day, not 24. The hours number shifts if you check it at different times of day. It changes by the hour, not just the date.

Seconds are the raw count. They are the building block for all other units. The number is large and abstract. At age 40 you have lived roughly 1.26 billion seconds. It is the most precise measure of how long you have existed.

Reading the visual bar

The coloured bar above the counters is a proportional representation. The filled portion shows the percentage of your assumed lifespan that has elapsed. The unfilled portion shows what remains.

If your bar is 60% filled, you have used 60% of your assumed time. The bar does not know your health, your genetics, or whether you will live to a very old age. It knows only the ratio of time elapsed to the number you entered.

The bar is useful for comparison. Change the lifespan assumption from 80 to 85, the filled portion shrinks. Change it to 75, the filled portion grows. This is the only place where you can see, in a single glance, how changing the assumption changes the picture.

Your birth date stays on your device

All calculations run in your browser. No birth date, no time, no lifespan figure is sent to any server. You can close the page, clear your cache, or disconnect from the internet while using it. The clock continues to work because it asks your browser for the current time, not a remote server.

Settings are not saved. If you customise the lifespan assumption to 82.5 years and reload the page, it resets to 80. That is intentional. Nothing is stored about you, because nothing needs to be.

Deeper articles on life expectancy and time

If the numbers on the display raise questions, the supporting articles answer them:

What Is a Life Clock? Definition and Meaning explains the concept behind the tool.
How Life Expectancy Is Calculated covers period versus cohort methods and why they differ.
How to Calculate Your Exact Age walks through the manual method if you want to verify the clock.
Life Expectancy by Country: Global Comparison Table gives you the data to choose your own number.

The life clock is a mirror. It reflects the ratio you choose to see. The numbers it shows are correct for the assumption you set. The question is whether the assumption fits your life, your country, and your willingness to look at what the bar reveals.