📅 周数计算器（日期加减周数、两个日期相隔几周）Week Calculator (Add or Subtract Weeks, Weeks Between Dates)

使用说明与常见问题How-to & FAQ

「周数计算器（日期加减周数、两个日期相隔几周）」是什么？What is the Week Calculator (Add or Subtract Weeks, Weeks Between Dates) tool?

在某个日期上加或减若干周（可再加零头天数），或算出两个日期之间相隔几周几天；结果给出星期几和 ISO 周数。起始日默认是今天（按你设备的日期）。本地处理。Add or subtract weeks (plus extra days) from a date, or find how many weeks and days lie between two dates. Results show the weekday and ISO week number. The start date defaults to today (your device's date). Processed locally.

如何使用「周数计算器（日期加减周数、两个日期相隔几周）」？How do I use the Week Calculator (Add or Subtract Weeks, Weeks Between Dates) tool?

在「周数计算器（日期加减周数、两个日期相隔几周）」中，填写「计算」、「起始日期」、「周数（减去填负数）」、「另加天数（可选）」、「结束日期」等参数，结果会随输入实时计算并显示在下方。In the Week Calculator (Add or Subtract Weeks, Weeks Between Dates): Fill in "Calculate", "Start date", "Weeks (negative to subtract)", "Extra days (optional)", "End date"; results are recalculated instantly as you type.

ISO 周数是什么？What is the ISO week number?

ISO 8601 规定每周从星期一开始，包含当年第一个星期四的那一周是第 1 周。所以 1 月初的几天可能属于上一年的最后一周。ISO 8601 weeks start on Monday, and week 1 is the week containing the year's first Thursday, so the first days of January can belong to the last week of the previous year.

起始日期默认是哪天？What is the default start date?

页面打开时自动填入你设备上的今天日期，每次打开都会更新，不会固定在某一天。When the page opens it fills in today's date from your device, so it is always current rather than fixed to one day.

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

例如在「周数计算器（日期加减周数、两个日期相隔几周）」中填 计算 = 日期加减周数，起始日期 = 2026-10-21，周数（减去填负数） = 6，结果区显示：结果日期：2026-12-02；星期：星期三；ISO 周：2026-W49；共计天数：42For example, entering Calculate = Add or subtract weeks, Start date = 2026-10-21, Weeks (negative to subtract) = 6 in the Week Calculator (Add or Subtract Weeks, Weeks Between Dates) gives: Result date: 2026-12-02; Weekday: Wednesday; ISO week: 2026-W49; Total days: 42

哪些输入会被检查？Which inputs are validated?

「周数计算器（日期加减周数、两个日期相隔几周）」会检查这些输入——「周数（减去填负数）」：须为不小于 -10,000且不大于 10,000的整数；「另加天数（可选）」：可留空；填写时须为不小于 -100,000且不大于 100,000的整数；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 Week Calculator (Add or Subtract Weeks, Weeks Between Dates) checks its inputs — "Weeks (negative to subtract)": must be at least -10,000 and at most 10,000 (a whole number); "Extra days (optional)": optional; if given it must be at least -100,000 and at most 100,000 (a whole number); 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?

「周数计算器（日期加减周数、两个日期相隔几周）」的设置：「计算」可选 日期加减周数、两个日期相隔（默认 日期加减周数）；「起始日期」可留空；「周数（减去填负数）」默认 6；「另加天数（可选）」可留空；「结束日期」默认 2026-12-25。每次生成结果都按当前设置处理。Settings in the Week Calculator (Add or Subtract Weeks, Weeks Between Dates) — "Calculate": Add or subtract weeks, Weeks between dates (default Add or subtract weeks); "Start date" optional; "Weeks (negative to subtract)" default 6; "Extra days (optional)" optional; "End date" default 2026-12-25. The result always uses the current settings.

时区如何处理？How are time zones handled?

「周数计算器（日期加减周数、两个日期相隔几周）」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 Week Calculator (Add or Subtract Weeks, Weeks Between Dates) 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.

「周数计算器（日期加减周数、两个日期相隔几周）」免费吗？需要注册吗？Is the Week Calculator (Add or Subtract Weeks, Weeks Between Dates) free? Do I need an account?

「周数计算器（日期加减周数、两个日期相隔几周）」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 Week Calculator (Add or Subtract Weeks, Weeks Between Dates) is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.