Age Calculator
Calculate exact age including years, months, and days from date of birth, and display next birthday and days alive
Features
Display age in years, months, and days
Calculate exact age down to the day, such as "36 years, 2 months, 29 days"
Freely change the reference date
Specify past or future dates to check age at different points in time
Also display next birthday and days alive
View days until next birthday, total days since birth, zodiac sign, and day of week born
Support for Japanese calendar input and traditional dating system
Input using Japanese eras like "Heisei 2" and view traditional age count, zodiac sign, school grade, and Japanese calendar format
How to Use
Enter your date of birth
Enter the year, month, and day. Year can be entered as Western calendar like "1990" or Japanese era like "Heisei 2" or "H2"
Change the reference date if needed
The reference date is pre-filled with today's date. Change it only when you want to check age at a different time
Check results and copy the information
View your exact age displayed immediately, along with traditional age count, next birthday, school grade, and other details
Use Cases
Filling out resumes and application forms
Verify your current age and date of birth in Japanese calendar format to accurately complete documents
Check child's age in months and school grade
Confirm "X years and Y months" and school grade at a specific date for childcare and education procedures
Check age at a past point in time
Set the reference date to your hire date or wedding date to check how old you were on that day
Plan milestone anniversaries
Count days until 10,000 days since birth or remaining days to next birthday for milestone anniversary planning
Basic Knowledge
Difference between age and traditional age count
- Age (Mannenrei)：Age is counted starting from 0 at birth and increases by 1 with each birthday. This is the age used in modern Japanese documents.
- Traditional age count (Kazoe-doshi)：Traditional age count starts at 1 at birth and increases by 1 with each New Year's Day. This is used as the basis for age-related celebrations and unlucky ages.
Why legal age advances on the day before your birthday
According to the Law on Age Calculation and the Civil Code's period calculation rules, legal age advances at the end of the day before your birthday. This is why children born on April 1st move up to the next school grade, though in everyday usage age increases on the birthday itself.
Birthday treatment for those born on February 29th
For people born on February 29th, their birthday does not exist in non-leap years. In everyday age counting, their birthday is typically treated as March 1st in non-leap years, while legally their age advances at the end of February 28th.
Safety and Privacy
Runs entirely in your browser
Your input data is processed only within your browser and is never sent externally.
Processing only in your browser
Age calculation is processed entirely within your browser, and input data is not sent to any server.
Communications encrypted with HTTPS
Page loading is also encrypted by TLS, and content cannot be read by third parties.
No transmission to third parties
Input content is not sent to external services such as ad networks or trackers.
No automatic saving of results
Entered date of birth and input suggestions are not stored on the server.
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Updates
- update #380
Age Calculator added. Display exact age in years, months, and days from date of birth, with support for days until next birthday and days since birth
Featured Tools
RAKKOTOOLS is free to use!
Available free of charge for individuals and corporations, commercial and non-commercial use alike.No prior permission or usage application is required. Feel free to use it in various situations.
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Can be used for commercial purposes such as research, calculation, processing, and conversion in business and production.
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If using in streaming and videos
Link to RAKKOTOOLS in the description, or Mention or display that you are using RAKKOTOOLS in the stream or video.
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Usage guidelinesYou are free to use it for normal purposes. However, use for purposes that violate laws, infringe on third-party rights, impose significant load on the service, or otherwise interfere with service operation is prohibited.
We do not guarantee the accuracy or completeness of information and calculation results obtained from each tool.
This notice is a translation of the original Japanese text. If there is any discrepancy between the translation and the original, the Japanese original takes precedence.