Age Calculator – Exact Age in Years, Months & Days
Welcome to the Age Calculator on Addition.site – the fastest, most accurate way to determine your exact age or the age difference between two dates. Simply enter a date of birth (or any past date) in the “yyyy‑mm‑dd” format, hit Calculate, and the result will be displayed instantly in years, months and days. The calculator is fully JavaScript‑based, so no page reloads are required and the result is immediately copy‑ready. And it's totally free to use and share.
How It Works
- Enter a Date – Use the calendar picker to choose your date of birth (or any earlier date).
- Click “Calculate” – The script subtracts the selected date from today’s date.
- View the Result – The output shows “X years, Y months, Z days” in a read‑only field.
- Copy or Share – Click the result field to copy it to your clipboard (you’ll see a “Copied!” toast). Use the 𝕏 button to share the age on X (formerly Twitter).
What the Calculator Gives You
- Exact Age – Years, months, and days are calculated with month‑length adjustments and leap‑year awareness.
- Age Difference – By using the same calculator on two dates (or re‑using the script manually), you can determine how many years, months, and days separate any two dates.
- Legal & Planning Tool – Quickly verify age for legal documents, event planning, travel restrictions, or birthday countdowns.
Why It’s Accurate
- Month & Day Adjustment – If the current day is before the birth day, the month count is decremented and days are added from the previous month.
- Year Adjustment – If the month count becomes negative, a year is subtracted and 12 months are added.
- Leap Years Handled Automatically – The algorithm uses JavaScript’s
Dateobject, which internally accounts for February 29th.
Tips & Best Practices
- Past Dates Only – The calculator works best with dates in the past; future dates will return 0 or negative values.
- Time Zone Consistency – The calculation uses the browser’s local time zone, so the result reflects your local date.
- Copy & Paste – Clicking the result field copies the text; you can paste it into documents, spreadsheets, or messaging apps.
- Share on X – The 𝕏 button creates a pre‑filled tweet with your age, making it easy to brag or share with friends.
Use Cases
| Scenario | How the Calculator Helps |
|---|---|
| Birthday Planning | Know your exact age for milestone celebrations. |
| Legal Verification | Confirm age requirements for voting, driving, or alcohol purchase. |
| Travel & Visa | Ensure you meet age criteria for travel documents. |
| Health & Fitness | Track age-related metrics for personalized programs. |
| Family History | Compare ages of relatives or determine generational gaps. |
About Addition.site
Addition.site is a free, web‑based utility hub that offers simple tools for everyday calculations. Our Age Calculator is built with clean, responsive HTML and vanilla JavaScript, ensuring fast performance on any device. No sign‑up required – just choose a date, click calculate, and enjoy instant results.
Start calculating your exact age(s) today – Free! No registration required, just pure, accurate age data.