🟩 平方毫米 ↔ 公亩Square millimetre to Are
平方毫米与公亩互算（1 mm² = 1e-08 a）。本地换算，附常用相关单位。Convert square millimetre and are (1 mm² = 1e-08 a). Runs locally with related units.
点击任意一行可复制该结果；小于 0.0001 或不小于 10¹⁵ 的数值用 × 10ⁿ 科学计数法显示Click any row to copy that result. Values below 0.0001 or at least 10¹⁵ are shown in × 10ⁿ notation
使用说明与常见问题How-to & FAQ
「平方毫米 ↔ 公亩」是什么？What is the Square millimetre to Are tool?
平方毫米与公亩互算（1 mm² = 1e-08 a）。本地换算，附常用相关单位。Convert square millimetre and are (1 mm² = 1e-08 a). Runs locally with related units.
如何使用「平方毫米 ↔ 公亩」？How do I use the Square millimetre to Are tool?
在「平方毫米 ↔ 公亩」中输入数值并选择原单位，表格会同时列出换算到所有其他单位的结果，可一键复制。Enter a value in the Square millimetre to Are and choose the source unit; the table shows the value in every other unit at once, ready to copy.
1 平方毫米等于多少公亩？How many are in 1 square millimetre?
1 mm² = 1e-08 a（按国际定义系数）。1 mm² = 1e-08 a (international definition).
如何把平方毫米换算成公亩？How do I convert square millimetre to are?
结果 = 数值 × 1e-08。例如 100000000 mm² = 1 a。result = value × 1e-08. Example: 100000000 mm² = 1 a.
平方毫米/公亩属于哪类单位？What kind of units are square millimetre/are?
二者同属「面积」量纲，可安全互算；也可打开「area-converter」做多单位对照。Both are area units; see also the area converter hub.
换算系数准确吗？Are the conversion factors exact?
「平方毫米 ↔ 公亩」采用国际单位制（SI）或公认标准中的定义值作为换算系数，结果保留约 10 位有效数字。The Square millimetre to Are uses factors defined by the SI or other recognised standards and shows about 10 significant digits.
「平方毫米 ↔ 公亩」免费吗？需要注册吗？Is the Square millimetre to Are free? Do I need an account?
「平方毫米 ↔ 公亩」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 Square millimetre to Are is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.