Calculator Lock – HideX for Android

Calculator Lock – HideX 3.5.17.4 is an Android app from Flatfish Studio that works as a working calculator on the surface and as a private vault underneath. Entering your secret PIN in the calculator opens a hidden space for photos, videos, files and even apps you want to keep private. The app is free, and you can download Calculator Lock – HideX for Android from your phone's app store.

Who HideX is for

Phones are shared more often than we admit: a child playing a game, a colleague looking at holiday pictures, a partner checking a message. A vault app suits people who want to keep certain photos, documents or chats out of casual view in those moments, for example ID scans, medical records, private pictures or work files on a personal phone. The calculator disguise means the vault does not advertise itself on the home screen. It is not, however, a replacement for proper device security. Someone who knows about the app, or has full access to your unlocked phone and time, can find it. And because everything is stored inside one app, the biggest risk is losing access to your own files: forgetting the PIN, uninstalling the app or switching phones without a backup can make the contents unrecoverable. People who mainly want stronger overall privacy should first set a strong screen lock and use the phone's built-in secure folder or private space if it has one.

Key facts

Setting it up safely

1. Install the app from your phone's official app store; the developer's site is flatfishsafe.com.
2. Choose a PIN you will remember but others cannot guess.
3. Set up the recovery option the app offers, such as a security question or email.
4. Move a few test files in and out before trusting it with important ones.
5. Keep a separate backup of anything you cannot afford to lose.

Before uninstalling or changing phones

Move everything out of the vault first. Uninstalling the app can delete the hidden files along with it, and a new phone does not automatically get your vault.

Permissions and ads

A vault needs access to the files you hide and possibly to other apps if you use the app-hiding feature. Free vault apps are usually financed by ads or premium features; read the privacy policy and in-app purchase terms.

Pros and cons

• Pro: hides photos, videos and files behind a calculator.
• Pro: works as a real calculator for casual use.
• Pro: free.
• Con: losing the PIN or app can mean losing the files.
• Con: not a substitute for a strong screen lock.

Alternatives

AppLock in our listings locks individual apps with a PIN or fingerprint. For ordinary calculations, Mi Calculator and Fraction Calculator Plus are simple calculators without hidden features.