🎩 帽子尺码换算Hat Size Converter

使用说明与常见问题How-to & FAQ

「帽子尺码换算」是什么？What is the Hat Size Converter tool?

按头围换算美码（头围英寸 ÷ π）、英码（美码 - 1/8）、欧码（厘米）和字母尺码。本地处理。Convert head circumference to US size (inches ÷ π), UK size (US - 1/8), European (cm) and letter sizes. Processed locally.

如何使用「帽子尺码换算」？How do I use the Hat Size Converter tool?

在「帽子尺码换算」中，填写「头围 cm」等参数，结果会随输入实时计算并显示在下方。In the Hat Size Converter: Fill in "Head circumference cm"; results are recalculated instantly as you type.

怎么量？How to measure?

软尺绕额头眉上约 1 cm、耳上，经后脑最突出处一圈。Wrap a soft tape around the forehead about 1 cm above the brows, above the ears and round the back of the head.

能举个计算实例吗？Can you show a worked example?

例如在「帽子尺码换算」中填 头围 cm = 57，结果区显示：美码：7 1/8；英码：7；欧码：57；字母：M；头围英寸：22.44For example, entering Head circumference cm = 57 in the Hat Size Converter gives: US size: 7 1/8; UK size: 7; EU size: 57; Letter: M; Inches: 22.44

哪些输入会被检查？Which inputs are validated?

「帽子尺码换算」会检查这些输入——「头围 cm」：必须填写，须大于 0；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 Hat Size Converter checks its inputs — "Head circumference cm": required, must be greater than 0; 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?

「帽子尺码换算」的设置：「头围 cm」默认 57。每次生成结果都按当前设置处理。Settings in the Hat Size Converter — "Head circumference cm" default 57. The result always uses the current settings.

换算系数准确吗？Are the conversion factors exact?

「帽子尺码换算」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 Hat Size Converter uses factors defined by the SI or other recognised standards and shows about 10 significant digits.

「帽子尺码换算」免费吗？需要注册吗？Is the Hat Size Converter free? Do I need an account?

「帽子尺码换算」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 Hat Size Converter is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.