⚖️ 单位比率计算器Unit Rate Calculator
把“多少 A 对应多少 B”化为单位比率（每 1 个 B 对应多少 A），例如 300 公里 / 4 小时 = 75 公里/小时；也可同时比较两个比率的高低（单价越低越划算，每元能买到的数量越高越划算）。Turn a rate like "A per B" into a unit rate — the amount for one unit of B — e.g. 300 km in 4 hours = 75 km per hour, and optionally compare a second rate to see which is the better deal.
使用说明与常见问题How-to & FAQ
「单位比率计算器」是什么？What is the Unit Rate Calculator tool?
把“多少 A 对应多少 B”化为单位比率（每 1 个 B 对应多少 A），例如 300 公里 / 4 小时 = 75 公里/小时；也可同时比较两个比率的高低（单价越低越划算，每元能买到的数量越高越划算）。Turn a rate like "A per B" into a unit rate — the amount for one unit of B — e.g. 300 km in 4 hours = 75 km per hour, and optionally compare a second rate to see which is the better deal.
如何使用「单位比率计算器」？How do I use the Unit Rate Calculator tool?
在「单位比率计算器」中，填写「数量 A（分子）」、「数量 B（分母）」、「A 的单位（可选）」、「B 的单位（可选）」、「比较：数量 A₂（可选）」等参数，结果会随输入实时计算并显示在下方。In the Unit Rate Calculator: Fill in "Amount A (numerator)", "Amount B (denominator)", "Unit of A (optional)", "Unit of B (optional)", "Compare: amount A₂ (optional)"; results are recalculated instantly as you type.
单位比率是什么？What is a unit rate?
单位比率是分母为 1 的比率，例如 75 公里/小时、每克 0.12 元。它让不同包装或速度可以直接比较。A unit rate has a denominator of 1, such as 75 km per hour or 0.12 per gram, so different package sizes or speeds can be compared directly.
比价时看哪个？Which one tells me the better deal?
若 A 是价格、B 是数量，单位比率就是单价，越低越划算；若 A 是数量、B 是价格，则越高越划算。If A is the price and B the quantity, the unit rate is the unit price — lower is better. If A is the quantity and B the price, higher is better.
计算精度如何？How precise are the results?
「单位比率计算器」使用 JavaScript 双精度浮点数（约 15–16 位有效数字）；极大或极小的数值可能存在精度误差。The Unit Rate Calculator uses double-precision floating point (about 15–16 significant digits); very large or very small values may lose precision.
「单位比率计算器」免费吗？需要注册吗？Is the Unit Rate Calculator free? Do I need an account?
「单位比率计算器」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 Unit Rate Calculator is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.