Editorial Policy
Published October 4, 2026. Last updated October 4, 2026.
A birthday tool is only useful if you can trust its answer. These are the rules every calculator and article on BdayChecker follows before it is published.
Who is responsible
Every tool and article is built or written, then reviewed and checked, by Daniel Hart, a software developer with more than 8 years of experience. Nothing is published until it has been checked.
The rule comes first
Each calculator explains its exact rule on the page: how months and days are counted, what happens on February 29, which time zone is used and who defines a date or a range. If you want to, you can check any result by hand.
Tested on the hard dates
Before a tool goes live, its calculations are tested with answers worked out separately. The tests cover leap days, month ends, New Year's Eve and the Lunar New Year boundary, in more than one time zone. The tests run again whenever a rule changes.
Facts come from their source
Every fact is checked against an authoritative, public source before it is published, and the source and date checked are recorded. Examples:
- Birthday statistics, such as how common your birthday is, come from US birth records published by the CDC and the Social Security Administration.
- Generation years follow the Pew Research Center.
- Retirement ages follow the Social Security Administration.
- Birthstones follow the American Gem Society, and birth flowers The Old Farmer's Almanac.
Entertainment is labeled
Zodiac, numerology, lucky number and compatibility tools are clearly marked as for entertainment. They explain the traditional method and sources used, and are not predictions or scientific claims.
Independent and ad-supported
BdayChecker is paid for by ads. Advertisers have no say in what we publish, and we do not accept payment to include, change or rank any content.
Updates and corrections
Pages are reviewed when a source publishes new data or a rule changes. If you find a mistake, email contact@bdaychecker.com with the page and what looks wrong. Every report is checked against the source, and the page is fixed if it is wrong.
Your data
Tools are built so the dates you enter stay in your browser. See the Privacy Policy for details, or try the Age Calculator to see how a tool explains its rule.