無料オンライン年齢計算機

The calculator counts complete calendar years first, then remaining complete months, then remaining days — matching how ages are counted officially on passports and legal documents.

Yes. Change the "As of" date field to any date you want. This is useful for calculating age at retirement, historical ages, or eligibility dates.

Leap years and varying month lengths can cause a 1-day difference in edge cases (e.g. birthdays on Feb 29 or month-end dates). The calculator uses ISO 8601 date arithmetic for maximum accuracy.

Yes. The results include your total age in days, hours, and even minutes from your birth time (midnight assumed if no time is entered).

The calculator gives the mathematically correct age. For official legal documents, always verify with a government-issued ID — do not rely solely on this tool.

Yes, the 年齢計算機 on Allio Tools is completely free with no sign-up or registration required. It works directly in your browser.

任意の誕生日から年、月、日、時間、分単位で正確な年齢を計算します。 No data is sent to a server — everything runs locally in your browser for maximum privacy and speed.

No installation needed. The 年齢計算機 runs entirely in your web browser on any device — desktop, tablet, or mobile.

Completely safe. The 年齢計算機 processes everything locally in your browser. No input data, results, or usage information is ever transmitted to or stored on any server.

After the page loads for the first time, the 年齢計算機 works without an internet connection for all client-side processing. Tools that fetch live external data (such as DNS or network lookups) require an active connection.

The 年齢計算機 uses standard, well-established mathematical formulas used by professionals worldwide — the same ones used by banks, financial advisors, and accounting software. Results are as accurate as the inputs you provide. See our <a href="/methodology/">Methodology page</a> for formula sources and references. For financial decisions, always verify with a qualified professional.

Yes. Copy the result number or screenshot the page to share via message, email, or social media. You can also bookmark and share the tool URL directly — the 年齢計算機 opens instantly for anyone with a modern browser, no account needed.

Yes. The 年齢計算機 is built with standard browser APIs and works on all modern browsers including Chrome, Firefox, Safari, and Edge — on both desktop and mobile. No plugins, extensions, or third-party software are required.

Select and copy the result text to paste into any document or app. For image tools, a Download button saves the file directly to your device. Your browser's built-in screenshot function also captures results quickly. No account or login is required.