How to use a calculator vault: set it up, hide photos and get back in

A calculator vault looks and works like an ordinary calculator, until you type a secret code and your hidden photos appear. If you've just installed one, or found one on your phone and aren't sure how it works, here's how to set one up, hide photos in it, open it again and turn the disguise off. We use Hidey's calculator disguise as the worked example, then cover how other calculator vaults usually differ.

How calculator vaults work

Every calculator vault follows the same idea. On your home screen it's a calculator, and if someone opens it, they get a calculator that really adds up. The vault only opens when you type your secret code, usually followed by the = key. Our explainer on calculator vault apps covers what the disguise hides and where it still shows.

Step by step with Hidey

1. Set up the vault with a PIN

Install Hidey, choose a PIN of 4 to 12 digits and hide a few photos so there's something to protect. The calculator needs a PIN rather than a password, because a calculator only has digits.

2. Turn on the calculator disguise

In Hidey, open Settings → Security → Disguise.
Choose Calculator, read what changes, and tap try it.
On the practice calculator, type your PIN and press =.
Tap turn on the disguise.

The practice step is there for a reason: the calculator has no "forgot PIN" button and fingerprint can't open it, so Hidey makes sure you can get in with your PIN before it changes anything. The calculator disguise is free.

3. Leave Hidey and find the calculator

Once you leave Hidey, its icon and name change to Calculator. On some phones the old icon disappears from your home screen, and you add the new one from your app list like any other app.

4. Open the vault

Tap Calculator, type your PIN and press =. Anything else is just a sum: wrong PINs look like ordinary calculations, so whoever tries gets a number, not an error.

5. Hide more photos

Inside the vault everything works as usual: pick photos from your gallery, take them with the secure camera, or add files. One difference: while disguised, Hidey leaves your phone's share menu, so its name doesn't appear when you share something. To hide a photo from another app, save it first, then hide it from inside Hidey.

6. Turn the disguise off

Open Settings → Security → Disguise and choose Hidey (no disguise). The usual icon comes back once you leave the app.

How other calculator vaults differ

Calculator vault apps from other makers follow the same pattern, but the details vary, so check these in the app's own help:

Setting the code. Many ask you to type a new passcode and press = on first launch, then repeat it to confirm.
The open key. Most use =, but some use another key, or open when you type the code with no key at all.
Recovery. Some offer a security question, a recovery email or a special reset code. Others can't recover at all. Find out before you need it.
Fingerprint. Some let a fingerprint open the vault, which is convenient but means anyone who can make you touch the sensor can open it.
Encryption. Many only hide files in a hidden folder. Here's how to check whether yours encrypts.

Getting back in if you forget the code

Forgetting the code is one of the easiest ways to lose photos in a calculator vault, because the disguise has no obvious "forgot" button by design. If the app has a recovery option, it's usually hidden too, so look it up in the app's help while you still remember your code. Here's how recovery works in popular vault apps, and the reset codes some calculator vaults use. Our guide to a forgotten vault PIN explains what to try, and what never to do, such as uninstalling the app or paying for an "unlocker".

With Hidey, recovery lives on the normal lock screen: tap forgot pin to reset it through Google after a 24-hour wait, or use your recovery key in zero-knowledge mode (Pro). The calculator doesn't show that option, so if you're not completely sure of your PIN, use one of Hidey's icon disguises instead. Clock, Weather and Notes (Pro) change the icon and name but keep the normal lock screen, with its forgot pin option. More on disguising apps on Android.

A few habits that help

Use a PIN you won't forget, and not the one that unlocks your phone.
Keep a backup. Hidey backs up to a hidden folder in your own Google Drive, encrypted before upload. Whoever controls that Google account could reset your PIN after the 24-hour wait, unless zero-knowledge mode (Pro) is on.
Watch the Download/Hidey folder. Unhidden photos go back to the folder they came from, but those without one, such as secure-camera photos, go to Download/Hidey, a name that gives the app away. Move them somewhere else after unhiding.
Remember what a disguise can't hide. Android's Settings and Google Play still list the app by its real name. The disguise is there to avoid attention. The encryption underneath is what protects your photos.