Most versatile
Age Calculator
Use the age calculator to find exact age in years, months and days, check another date, or estimate a possible birth-date range.
Try: How old am I today?Open Age CalculatorFree online date calculators
Date and Time Calculators
Choose the calculator that matches your question. Find an exact age, compare two birthdays, count days lived, or plan the next milestone. Every result shows how the date was counted.
Date and time calculator directory
Choose a date calculator
Start with the general age tool, or pick a focused calculator when you already know the date or milestone you need.
Age Difference Calculator
Use the age difference calculator to compare two dates of birth, find the exact age gap, and see the total days apart.
Try: Compare two dates of birthOpen Age Difference CalculatorAge in Days Calculator
Use the age in days calculator to find how many days old you are, convert to weeks, and calculate 10,000-day milestones.
Try: Find your 10,000-day birthdayOpen Age in Days CalculatorBirthday Calculator
Use the birthday calculator to find your next birthday date, weekday, countdown, age reached and leap-day birthday convention.
Try: Count down to your next birthdayOpen Birthday CalculatorHalf Birthday Calculator
Use the half birthday calculator to find your next half birthday by six calendar months or the exact midpoint between birthdays.
Try: Find your half-birthday dateOpen Half Birthday CalculatorCalculator chooser
Match your question to the right tool
Choose the closest question below. Each calculator focuses on one kind of answer, so the inputs stay simple.
| Your question | Best calculator | What it finds |
|---|---|---|
| How old am I today or on another date? | Age Calculator | Years, months and days |
| What is the age gap between two people? | Age Difference Calculator | Age gap and total days |
| How many days old am I? | Age in Days Calculator | Days, weeks and milestone dates |
| When is my next birthday? | Birthday Calculator | Date, weekday, age and countdown |
| When is my half birthday? | Half Birthday Calculator | Six-month date or true midpoint |
How the calendar maths works
Real calendar dates, not rough averages
These tools work with calendar dates only. Exact age counts full years, then full months and remaining days. Day-count results count the actual calendar days, including leap years and short or long months.
Dates stay in your browser and are never added to analytics or share URLs. Where there is more than one common choice, such as a 29 February birthday or a half birthday, the calculator shows the choice instead of hiding it.
Date and time guides
Understand the calendar methods
Use the guides to calculate an answer by hand, check a worked example, or understand leap-day and day-count rules.
How to Calculate Age
Learn how to calculate age from a date of birth in years, months and days, with simple steps, examples and common mistakes.
learn how to calculate ageWhat Is Chronological Age?
Chronological age means age counted from a date of birth. Learn the meaning, formula, examples and limits of calendar age.
understand chronological ageLeap-Year Birthdays Explained
Learn how 29 February birthdays work in non-leap years, why people use 28 February or 1 March, and how calculators handle them.
understand leap-year birthdaysAge in Days and Milestone Birthdays
Learn how age in days is counted and how to find 1,000, 5,000, 10,000 and other day-based birthday milestones.
plan a milestone birthdayCommon questions
About these date and time tools
A few quick answers to help you choose a calculator and understand its result.
Which calculator finds my exact age?
Use the Age Calculator for full years, months and days today or on another date. Its reverse mode also gives possible birth dates from a known age.
Which tool compares two people?
Use the Age Difference Calculator with both dates of birth. It shows who is older, the readable age gap and total days apart.
How do I find my 10,000-day birthday?
Use the Age in Days Calculator, choose the 10,000-day milestone and enter the date of birth.
Which calculator counts down to a birthday?
Use the Birthday Calculator for the next date, weekday, age reached and days remaining.
How is a half birthday calculated?
Use the Half Birthday Calculator and choose either six calendar months or the true halfway point between birthdays.