This tool compares weight and length with a WHO-adapted median reference for age and sex, then estimates the percentile band. The WHO growth standards were built from healthy, breastfed infants in six countries — they describe how children should grow, not how the local average happens to look. Doctors care most about the trajectory: staying on roughly the same band across visits is the healthy pattern, while a sudden drop or jump across two or more bands deserves a conversation.
本工具将体重与身长与按年龄和性别调整的 WHO 参考中位值对比，估算百分位区间。WHO 生长标准取自六个国家健康母乳喂养婴儿——它描述的是孩子应当如何生长，而非当地平均值长什么样。医生最看重的是趋势：多次随访中保持在相近区间是健康模式，而跨两条及以上曲线突然下滑或跃升则需要沟通。
