Show week numbers in Google Calendar, Outlook, iPhone, Android

Big parts of Europe run on calendar weeks. "Let's ship in week 34." "The parts arrive in week 41." Then you open your calendar app and there's no week number in sight.

The setting exists in almost every calendar. Each app just buries it somewhere different, Outlook ships with it switched off, and the Google Calendar apps on Android and iPhone don't have the option at all.

Here's where the switch hides in every major calendar, plus the one workaround that puts week numbers on your phone even when the app refuses to offer them.

The short answer#

To show week numbers in Google Calendar, open the desktop site, click the gear icon, then Settings, then View options, and check "Show week numbers". In Outlook, the setting sits under File, Options, Calendar (classic) or under the settings gear, Calendar, View (new Outlook and Outlook.com). On iPhone, go to Settings, Apps, Calendar and turn on Week Numbers. On Android it depends on the app: Samsung Calendar has a toggle in its settings, the Google Calendar app has none.

Every app counts 52 or 53 weeks per year. Whether they all show the same number for the same day depends on a second setting, covered further down.

Google Calendar: the setting lives on desktop only#

1. Open Google Calendar in a desktop browser.
2. Click the gear icon at the top right, then Settings.
3. Under General, open View options.
4. Check Show week numbers.

The numbers appear right away in the left margin of month view and beside the little mini calendar in the sidebar.

Google uses ISO 8601 numbering: weeks run Monday to Sunday, and week 1 is the week containing the year's first Thursday. Set "Start week on" to Monday in the same View options block so the rows line up cleanly with the numbers.

The setting saves to your Google account and follows you across browsers. It does not follow you to your phone.

The Google Calendar app has no week numbers#

Search the Android or iPhone app settings as long as you like. There's no toggle. The option exists on the desktop site only, and enabling it there changes nothing in the apps. Users have been asking Google for it for years.

You have 2 real options on a phone:

The browser. Open calendar.google.com in Chrome or Safari and request the desktop site. The numbers show up, but the layout is cramped. Fine in a pinch, annoying every day.

A subscribed week number calendar. This is the fix I'd actually use, and it works in every app on this page.

Put week numbers in any calendar with an iCal feed#

A week number calendar is a small iCal feed with one all-day entry at the start of each week: week 31, week 32, and so on. Subscribe once and the numbers appear inside every app that syncs your calendars, including the Google Calendar app on Android and iPhone, Outlook mobile, and your smartwatch.

WeekIsIt publishes a free week number calendar you can subscribe to. Adding it takes about a minute:

• Google Calendar: on the desktop site, click the + next to "Other calendars", pick From URL, and paste the feed address. The subscribed calendar syncs to the mobile apps on its own; if it doesn't show, enable it once under the app's calendar list.
• iPhone: tap the feed link on your phone and confirm, or go to Settings > Apps > Calendar > Calendar Accounts > Add Account > Other > Add Subscribed Calendar.
• Outlook: in the calendar view, choose Add calendar, then Subscribe from web.

Because the numbers ride along as normal calendar entries, this route works even where no setting exists. Right now it's the only way to get week numbers into the Google Calendar phone apps.

Outlook ships with week numbers switched off#

Outlook supports week numbers in every desktop and web version. It also turns them off by default, which is why so many people assume the feature is missing.

Classic Outlook for Windows:

1. Go to File > Options > Calendar.
2. Scroll to Display options.
3. Check Show week numbers in the month view and in the Date Navigator.
4. Click OK.

The numbers appear in month view and in the small Date Navigator calendar. Classic Outlook leaves them out of day and week view, a long-running user complaint. Outlook on the web shows them in week view too.

New Outlook and Outlook.com: click the settings gear, open Calendar, then View, and switch on Show week numbers. The same screen holds "First day of the week" and "First week of the year".

Those 2 dropdowns decide which number you see. For the ISO 8601 numbers used across Europe (and by WeekIsIt), pick Monday as the first day and First 4-day week as the first week of the year. Classic Outlook has the same 2 settings in the Options window. The "Starts on Jan 1" choice produces US-style numbering instead, and the 2 systems disagree at every year boundary.

Outlook mobile has no week number setting. Use Outlook on the web from your phone's browser, or subscribe to the feed above.

iPhone and iPad: one toggle in Settings#

Apple keeps the switch outside the Calendar app:

1. Open Settings.
2. Tap Apps, then Calendar. On older iOS versions, Calendar sits directly in the main Settings list.
3. Turn on Week Numbers.

Month view now shows a small gray number at the left of every week row. Day and week view stay unchanged.

Which number you get depends on your region. iPhones set to most European regions start weeks on Monday and match ISO 8601. A device on United States settings starts weeks on Sunday and counts week 1 from January 1, so its numbers can sit 1 off from a colleague's near the turn of the year. You can force the start day under Settings > Apps > Calendar > Start Week On.

On a Mac, the same option lives in Calendar > Settings > Advanced > Show week numbers.

Android: depends entirely on the app#

Android has no system-wide week number switch, so your calendar app decides.

Samsung Calendar has the toggle: open the app, tap the menu (3 lines, top left), tap the gear icon, and enable Show week numbers. The numbers run down the left side of month view.

One known trap: Samsung derives the numbering rule from your device language and region. On US English, the count can run 1 ahead of ISO for part of the year, and Samsung's own forums are full of exactly this complaint. Switching the device to a Monday-start locale such as English (UK) fixes it.

Google Calendar app: no option, as covered above. The subscribed feed is the workaround.

Third-party apps: Business Calendar 2, aCalendar and DigiCal all display week numbers and let you pick the numbering system. If you plan by calendar week daily and your stock app won't cooperate, switching apps is a fair trade.

Why your apps disagree on the week number#

2 systems dominate. ISO 8601 starts weeks on Monday and calls week 1 the week containing the year's first Thursday. The US system starts weeks on Sunday and calls week 1 whichever week contains January 1.

Most of the year they agree. At the year boundary they split. Friday, January 1, 2027 sits in week 53 of 2026 under ISO and in week 1 of 2027 under US counting. Same day, 2 different answers.

And yes, 2026 really has 53 weeks: ISO week 53 runs Monday, December 28, 2026 to Sunday, January 3, 2027.

To make every device agree, set each one to Monday as the first day of the week and, where the option exists, "First 4-day week" as the first week of the year. Then cross-check any date with the week calculator or scan the full 2026 week calendar.

FAQ#

Quick reference:

• Google Calendar web: gear > Settings > View options > Show week numbers
• Outlook: File > Options > Calendar (classic) or gear > Calendar > View (new Outlook, Outlook.com)
• iPhone: Settings > Apps > Calendar > Week Numbers
• Samsung: Calendar app > menu > gear > Show week numbers
• Any phone app without a setting: subscribe to the WeekIsIt week number calendar
• Check any date's number with the week calculator

Sources and further reading:

• Microsoft Support: Turn on or off week numbers in Outlook
• Apple Support: Change your Calendar settings on iPhone
• Samsung: How to use the Calendar app on a Galaxy smartphone
• Wikipedia: ISO week date