What happens with February 29 birthdays in non-leap years?

In non-leap years the calculator uses February 28 as the anchor date for Feb 29 birthdays, so the age increments on Feb 28.

Age Calculator — Exact Age in Years, Months & Days

Q: How do I calculate my exact age in years, months, and days?

Enter your date of birth and select a reference date. The calculator uses calendar arithmetic to count complete years, remaining months, and remaining days, correctly handling leap years and variable month lengths.

Q: How are business days calculated?

Business days exclude Saturdays and Sundays. Toggle 'business days only' and the calculator skips weekends. Public holidays are not automatically excluded as they vary by region.

Q: Is my date of birth stored or transmitted?

No. All calculations run client-side in your browser. No data leaves your device.

Q: Why does adding one month to January 31 give March 3?

February only has 28 days (or 29 in a leap year), so 'January 31 plus one month' has no exact match. The calculation rolls forward to the next valid calendar date — the 3rd of March in most years.

Date of Birth

Age as of Use today's date

Start Date

End Date Use today as end date

Business days only (exclude weekends)

Starting Date

Operation

Add Subtract

Duration

Years

Months

Days

Skip weekends (business days only)

Result

Next Birthday

How to Calculate Your Age Exactly

Most people know their age in whole years, but there are dozens of situations where you need precision down to months, weeks, or even days. Medical eligibility cutoffs, visa applications, insurance underwriting, retirement planning, and legal proceedings all depend on an exact age on a specific date — not just the year you were born.

Our age calculator does more than subtract years. It accounts for the variable length of months, leap years, and calendar edge cases like February 29 birthdays. You get your age broken down into years, months, and days, plus the complete running totals: exactly how many weeks you have been alive, how many days, and how many hours. For newborns and toddlers, weeks and days are often the most meaningful unit — pediatricians track development this way, and so can you.

Days Between Dates — The Versatile Date-Difference Tool

Beyond personal age, the date-difference mode handles any two calendar dates. Project managers use it to count days between a kickoff and a deadline. HR teams confirm probationary periods. Landlords calculate lease lengths. Students count days until exams. Toggle the business-days filter and weekends are excluded automatically — giving you the true working-day count without manual counting on a calendar.

The date difference tool works in both directions and handles multi-year spans correctly. Whether you need the number of calendar days between two contract dates or the exact number of working days remaining in a project, this tool delivers the precise count immediately.

Add or Subtract Time from Any Date

Need to know what date falls 90 days from today? Or what date was 6 months before a contract started? The add/subtract mode accepts years, months, and days independently. It handles month-end boundaries correctly — when you add one month to January 31 and February has no 31st, the result rolls forward to March 3rd, and the result card notes this adjustment. You also see the day of the week for the resulting date.

This mode is particularly useful for legal and business deadlines where contract clauses specify durations in months or years rather than calendar days. Enter the start date, set the duration, and the result is instant.

Next Birthday Countdown

Enter a date of birth and the calculator automatically shows how many days, hours, and minutes remain until the next birthday — and which age will be celebrated. The countdown updates based on the current system time. For birthdays falling on February 29 in non-leap years, the calculator uses February 28 as the anchor date, matching the most common legal interpretation. The zodiac sign for the entered date of birth is also displayed — useful for astrology fans, greeting card selections, and personality quizzes.

Privacy and Accuracy

All calculations run entirely in your browser using JavaScript. No personal data — including your date of birth — is sent to any server. The calculator uses standard calendar arithmetic with correct leap year handling (divisible by 4, except centuries unless also divisible by 400). Results may differ slightly from legal age determinations in jurisdictions with specific birthday rules; always confirm important age thresholds with a qualified professional.

Frequently Asked Questions

How do I calculate my exact age in years, months, and days? ▼

Enter your date of birth and select a reference date (or use today's date). The calculator uses calendar arithmetic to count complete years first, then remaining complete months, then remaining days — accounting for leap years and variable month lengths. The result also includes total weeks, total days, total hours, and total minutes alive.

How are business days calculated? ▼

Business days exclude Saturdays and Sundays. Enable the "business days only" toggle in the Date Difference tab and the calculator skips weekends while counting the span between your two dates. Public holidays are not automatically excluded because they vary by country and employer — you can manually adjust the result.

What happens with February 29 birthdays? ▼

In years without a February 29, the calculator uses February 28 as the birthday anchor. This means a person born on Feb 29, 2000 turns a whole number of years on Feb 28 in non-leap years. The next birthday countdown reflects this same logic.

Is my date of birth stored or transmitted anywhere? ▼

No. All calculations run client-side in your browser using JavaScript. No data is transmitted to any server. Your most recently entered dates are saved in your browser's localStorage (prefixed "launchbay_v1_age-calculator_") purely for your convenience — so your inputs are restored next time you visit. You can clear this at any time by clearing your browser's site data.

Why does adding one month to January 31 give March 3? ▼

February only has 28 days (or 29 in a leap year), so "January 31 plus one month" has no exact match in the calendar. JavaScript's Date object rolls forward to the next valid date — March 3 in most years. The result card displays a note whenever this overflow adjustment occurs, so you are always aware of the rounding.