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Is Check Calendar Safe?

Check Calendar privacy label · by Naoki Otsu · checked November 2026

  • Tracks you
  • Recently updated
App Privacy label Developer-reported · checked November 1, 2026
Used to track you
1type
Linked to you
0types

None declared

Not linked to you
3types
Short answer

It depends on how you feel about tracking: Check Calendar declares data used to track you. None of it falls in Apple's most sensitive categories (health, financial, location, contacts or your own content). In total the label lists 3 data types; 41% of calendar planners we checked declare tracking.

At a glance

Check Calendar privacy in one look

Data exposure on the label
Used to track you
  1. 1
  2. 2
  3. 3
  4. 4

Built only from the developer's App Store label. It describes disclosure, not tested behaviour.

Verdict from the label
Tracks you

Check Calendar's developer reports using diagnostics to track you across other companies' apps and websites.

Try it

Did Check Calendar ask for something?

Pick the permission prompt you saw. We compare it with what Check Calendar's developer declared.

It asked me for access to…
Tap a prompt to compare it with the label.
Not on the label

Location is not on Check Calendar's label. That can be fine: data used only on your iPhone does not have to be declared. If the data would need to leave the phone for the feature to work, ask why it is missing.

Not on the label

User Content is not on Check Calendar's label. That can be fine: data used only on your iPhone does not have to be declared. If the data would need to leave the phone for the feature to work, ask why it is missing.

Not on the label

Contacts is not on Check Calendar's label. That can be fine: data used only on your iPhone does not have to be declared. If the data would need to leave the phone for the feature to work, ask why it is missing.

Expected — and you can decline

Check Calendar declares data used to track you, so expect the “Allow to track?” prompt. Tap Ask App Not to Track; the app must keep working without it.

Not on the label

Health & Fitness is not on Check Calendar's label. That can be fine: data used only on your iPhone does not have to be declared. If the data would need to leave the phone for the feature to work, ask why it is missing.

A permission is what the app can reach on your iPhone; the label is what the developer says leaves it. They answer different questions.

Line by line

What Check Calendar collects, explained

Data typeWhat it coversWhere to limit it
IdentifiersNot linked to you An account ID, screen name, customer number or a device-level ID such as the advertising identifier. Settings › Privacy & Security › Tracking: turn off Allow Apps to Request to Track, or tap Ask App Not to Track when prompted.
Usage DataNot linked to you What you tap, open and view inside the app, plus which ads you have seen. There is no single iOS switch. Look for an analytics or personalised-ads toggle in the app's own settings.
DiagnosticsUsed to track youNot linked to you Crash logs, launch times, hang rates and energy use. Settings › Privacy & Security › Analytics & Improvements › Share With App Developers controls what Apple passes on; the app's own crash reporting is separate.
Reading the label

What Check Calendar's label means for you

Check Calendar's label has 1 type under “Data Used to Track You”, 3 types under “Data Not Linked to You”. A data type can appear in more than one section when it is used for different purposes — for example, identifiers used for both analytics and advertising.

Tracking is the declaration that most separates apps. It means diagnostics from Check Calendar can be combined with data from other companies to target or measure ads, or shared with data brokers. On iOS 14.5 and later, the app must ask your permission before tracking you through the advertising identifier; answering “Ask App Not to Track” blocks that identifier and tells the developer you have declined.

None of the data types fall into the categories most people consider sensitive: health, financial information, precise location, contacts, browsing history or the content you create.

Calendars reveal where you will be and who you meet. Planner apps may also read your other calendars and reminders. Check the Calendars permission level (full access or add-only) in Settings › Privacy & Security › Calendars.

Among the 152 calendar planners in our snapshot with a label, 41% declare tracking, 60% collect data linked to you and 26% say they collect nothing. Check Calendar lists 3 data types, about the same as the average of 2.9 for this group.

Productivity apps tend to collect the work you do in them — documents, notes and files — so User Content is common. The question is whether it syncs to the developer's servers and how it is protected there.

On your iPhone

Settings to check for Check Calendar

  1. 1

    Tracking

    Settings › Privacy & Security › Tracking. If “Allow Apps to Request to Track” is off, apps cannot ask, and they are told to treat you as having declined. You can also turn it off for this app alone.

  2. 2

    Lock the app

    On iOS 18 and later, touch and hold the icon and choose Require Face ID. Anyone who picks up your unlocked phone then needs your face, fingerprint or passcode to open it.

  3. 3

    Notifications

    Settings › Notifications › Check Calendar › Show Previews: When Unlocked keeps message and account details off the Lock Screen.

Cross-app tracking

Does Check Calendar track you?

Yes — 1 data type

Diagnostics. Apple defines tracking as linking data from this app with data from other companies' apps, websites or offline sources for targeted advertising or ad measurement, or sharing it with a data broker.

Does Check Calendar track you? Full answer and how to stop it →

iOS 18 and later

Lock Check Calendar behind Face ID

  1. Find Check Calendar on your Home Screen or in App Library.
  2. Touch and hold the icon until the quick-actions menu opens.
  3. Tap Require Face ID (or Require Touch ID / Require Passcode, depending on your iPhone).
  4. Tap Require Face ID again to confirm. Check Calendar now asks for authentication every time it opens.

The lock is an iPhone feature, so it works whether or not Check Calendar has a passcode of its own. It does not change what the app sends to its developer.

From the App Store record

About Check Calendar

DeveloperNaoki Otsu
App Store categoryProductivity (also Lifestyle)
Latest version14.53.2, released October 2026
First releasedApril 2021
RequiresiOS 15.1 or later
Size58 MB
Age rating4+
Languages24 (CS, DA, NL, EN, FR, DE, HI, HU…)
Bundle IDcom.checkcalendar

The current version shipped in October 2026, so the app is actively maintained and its label is likely current. Labels are updated by developers when practices change.

Also by Naoki Otsu: Password Manager Clipboard, Vertical Calendar.

Read with care

What the label cannot tell you

  • A label is self-reported. Apple publishes the developer's answers and can reject apps that misrepresent them, but it does not independently verify what Check Calendar sends.
  • It does not say where data is stored, how long it is kept, whether it is encrypted, or which companies receive it. The privacy policy covers those points.
  • Optional data counts: if a feature lets you add something (a profile photo, a phone number), the type is listed even if you never use the feature.
  • Data handled only on your iPhone is not 'collected', so a no-collection label is compatible with an app that reads your files locally.
  • Third-party sign-in, payment processors and SDKs are supposed to be included, but a label can lag behind a new version.

The question to ask Check Calendar's developer: Does it need to read my calendars, or only add events?

How it compares

Check Calendar vs similar calendar planners

Data types listed on each App Store privacy label
Tracks youLinked to youNot linkedCollects nothing

Fewer types is not automatically safer: a cloud backup app has to collect your files to work. Compare like with like.

Checking another app?

Look up any of our apps in seconds, or put two labels side by side.

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All calendar planners → Who tracks you? A–Z → Apps that collect identifiers → Privacy label decoder →

Do it now

Your Check Calendar privacy checklist

Tick what you have done
Tick each step as you do it on your iPhone.

Done. You have applied every control the label points to.

Quick quiz

True or false?

  1. Q1Check Calendar's privacy label says it uses data to track you.
    Right.
    Not quite.

    True: it lists diagnostics under Data Used to Track You.

  2. Q2Apple tests every app to confirm its privacy label is accurate.
    Right.
    Not quite.

    Labels are self-reported by developers. Apple can reject or remove apps that misrepresent practices, but it does not audit each label.

  3. Q3Check Calendar collects Identifiers.
    Right.
    Not quite.

    True: Identifiers appears on its label, in the Not Linked to You section.

  4. Q4Data “Not Linked to You” is never sent off your iPhone.
    Right.
    Not quite.

    It is collected and sent; the developer says it is de-identified rather than tied to your account or device.

  5. Q5Tapping “Ask App Not to Track” can stop an app from working.
    Right.
    Not quite.

    Apple's rules require apps to work the same whether or not you allow tracking.

Questions people ask

Check Calendar privacy FAQ

Is Check Calendar safe to use?
Based on its App Store privacy label, check Calendar's developer reports using diagnostics to track you across other companies' apps and websites. Whether that is acceptable depends on what you will store in it. The label is developer-reported, not an independent security test.
Does Check Calendar track you?
Yes. Its label lists diagnostics under Data Used to Track You. You can decline at the iOS tracking prompt.
What data does Check Calendar collect?
Identifiers, usage data and diagnostics. Of these, diagnostics is linked to your identity.
Who makes Check Calendar?
Naoki Otsu, according to the App Store. It was first released in April 2021 and the current version is 14.53.2.
Can I lock Check Calendar with Face ID?
On iOS 18 or later, touch and hold Check Calendar's icon and choose Require Face ID (or Touch ID / Passcode). This is an iPhone feature and works for most downloaded apps, whether or not the app has its own lock. If you don't see the option, update iOS.
How does Check Calendar compare with other calendar planners?
Across 152 calendar planners with labels in our snapshot, 41% declare tracking and 26% say they collect no data. Check Calendar lists 3 data types against an average of 2.9.
Does it need to read my calendars, or only add events?
The privacy label cannot answer that. Look for it in Check Calendar's privacy policy or support pages, linked from the App Store listing. Check the Calendars permission level (full access or add-only) in Settings › Privacy & Security › Calendars.
How do I delete my data from Check Calendar?
Apps that let you create an account must also let you start account deletion from inside the app (an App Store rule since June 2022). Deleting the app from your iPhone alone does not delete data already sent to the developer.
Facts on this page come from Check Calendar on the App Store, as reported by the developer. Checked 2026-11-01. How we collect data · Report a correction