🎂 出生年份计算器（按年龄和是否已过生日）Birth Year Calculator (from Age and Birthday)
由当前年龄和今年是否已过生日算出生年份；不确定是否已过生日时给出两个可能的年份。参考年份默认是今年，也可以改成任意年份。本地处理。Find the birth year from a current age and whether the birthday has passed this year; if you are not sure, both possible years are given. The reference year defaults to this year and can be changed. Processed locally.
使用说明与常见问题How-to & FAQ
「出生年份计算器（按年龄和是否已过生日）」是什么？What is the Birth Year Calculator (from Age and Birthday) tool?
由当前年龄和今年是否已过生日算出生年份；不确定是否已过生日时给出两个可能的年份。参考年份默认是今年，也可以改成任意年份。本地处理。Find the birth year from a current age and whether the birthday has passed this year; if you are not sure, both possible years are given. The reference year defaults to this year and can be changed. Processed locally.
如何使用「出生年份计算器（按年龄和是否已过生日）」？How do I use the Birth Year Calculator (from Age and Birthday) tool?
在「出生年份计算器（按年龄和是否已过生日）」中，填写「年龄（周岁）」、「今年生日」、「参考年份（可选，默认今年）」等参数，结果会随输入实时计算并显示在下方。In the Birth Year Calculator (from Age and Birthday): Fill in "Age (years)", "Birthday this year", "Reference year (optional, default this year)"; results are recalculated instantly as you type.
为什么要问生日过没过？Why does it ask about the birthday?
年龄在生日那天才加一。今年 30 岁、生日已过，就是 30 年前出生；生日还没到，说明今年要满 31，出生年份要再早一年。Age goes up on the birthday. If you are 30 and the birthday has passed, you were born 30 years ago; if it has not come yet you turn 31 this year, so you were born a year earlier.
能算虚岁吗？Does it handle East Asian age reckoning?
本页按周岁计算。传统虚岁出生时就算 1 岁、每过农历新年加 1 岁，换算出生年时一般用 当前年份 − 虚岁 + 1。This page uses the international age. Traditional East Asian age starts at 1 at birth and goes up at each Lunar New Year; for that, the birth year is usually the current year − that age + 1.
可以算过去或将来的年份吗？Can I use a past or future year?
可以，把参考年份改成任意年份，例如“1990 年时 25 岁的人”出生于 1964 或 1965 年。Yes. Set any reference year; someone who was 25 in 1990 was born in 1964 or 1965.
能举个计算实例吗？Can you show a worked example?
例如在「出生年份计算器（按年龄和是否已过生日）」中填 年龄（周岁） = 30，今年生日 = 已经过了，参考年份（可选，默认今年） = 2026，结果区显示：出生年份：1996；参考年份：2026；ℹ 已过生日：出生年 = 参考年 − 年龄；还没过：再减 1For example, entering Age (years) = 30, Birthday this year = Already passed, Reference year (optional, default this year) = 2026 in the Birth Year Calculator (from Age and Birthday) gives: Birth year: 1996; Reference year: 2026; ℹ birthday passed: birth year = reference year − age; not yet: subtract one more
哪些输入会被检查？Which inputs are validated?
「出生年份计算器（按年龄和是否已过生日）」会检查这些输入——「年龄（周岁）」：必须填写；「参考年份（可选，默认今年）」：不能为负数；绝对值超过 10¹⁵ 的数也会被拒绝。不符合时结果区显示具体提示，不会给出数字。The Birth Year Calculator (from Age and Birthday) checks its inputs — "Age (years)": required; "Reference year (optional, default this year)": cannot be negative; numbers above 10¹⁵ in absolute value are rejected too. When a value fails, the result area names the problem instead of showing a number.
有哪些选项可以调整？What options can I adjust?
「出生年份计算器（按年龄和是否已过生日）」的设置：「年龄（周岁）」默认 30；「今年生日」可选 已经过了、还没到、不确定（默认 已经过了）；「参考年份（可选，默认今年）」可留空。每次生成结果都按当前设置处理。Settings in the Birth Year Calculator (from Age and Birthday) — "Age (years)" default 30; "Birthday this year": Already passed, Not yet, Not sure (default Already passed); "Reference year (optional, default this year)" optional. The result always uses the current settings.
时区如何处理？How are time zones handled?
「出生年份计算器（按年龄和是否已过生日）」按日历日期计算，只有“今天”取自你设备的本地日期；计算不涉及钟点，所以时区和夏令时不影响结果。The Birth Year Calculator (from Age and Birthday) works with calendar dates; only "today" comes from your device's local date. No clock times are involved, so time zones and daylight saving time do not affect the result.
「出生年份计算器（按年龄和是否已过生日）」免费吗？需要注册吗？Is the Birth Year Calculator (from Age and Birthday) free? Do I need an account?
「出生年份计算器（按年龄和是否已过生日）」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Birth Year Calculator (from Age and Birthday) is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.