Hide Smartphones in Plain Sight (Hollow Book Stash)
A hollow-book container can hold one powered-off smartphone in plain sight without changing your home. Measure the phone and its case, allow at least 6 mm of extra length and width, and leave 3 mm above its thickness. Keep the lid pressure-free, place the book where it stays accessible, and never charge the phone inside.
If you have children at home, a familiar book can make a useful phone container, but it is not a childproof lock. Think about whether a child could reach it, mistake it for a toy, or need to use the phone in an emergency. If access matters, choose a visible, known storage spot instead of relying on concealment.
I treat this as a small storage project, not a building alteration. The goal is a neat-looking book that opens easily and protects the phone from pressure. A purpose-made book safe is the simplest option; modifying a book you own can also work if you remove material only from its pages and check the fit with care.
Planning the Container and Measuring the Device
A book safe is a movable container with a hollow space inside its pages or body. Before choosing one, measure the phone as it will be stored, including its case. These measurements are design allowances, not code requirements. A loose, unpowered book container does not create a building electrical installation.
Start with the device, not the book. Measure the phone’s length, width, and thickness with the case on. If you plan to store it without the case, measure it that way instead. Do not assume that a phone listed at a certain size will fit the cavity; the case, camera bump, and buttons can affect how it sits.
Use these minimum allowances:
- Cavity length: phone length plus at least 6 mm.
- Cavity width: phone width plus at least 6 mm.
- Cavity depth: phone thickness plus at least 3 mm.
- Lining: add the compressed thickness of any felt or foam to the measurements.
The space should let you lower the phone in and lift it out without forcing it. Extra room is useful, but a cavity that is much larger can let the phone shift when you move the book. If you add lining, keep it clear of buttons and avoid material that bunches beneath the screen.
For example, a phone that measures 150 mm by 72 mm by 8 mm needs a cavity at least 156 mm long, 78 mm wide, and 11 mm deep before you account for any lining. This is a starting point, not a guarantee of fit; the shape and position of the phone’s camera bump may call for more room.
Next step: Write down the phone’s three measurements and the dimensions of the cavity before buying or preparing a container.
Checking Fit, Access, and Shelf Clearances
Fit means more than whether a phone can enter the cavity. It must rest without pressure, the cover must close freely, and you must be able to retrieve the device without pulling apart the book. The shelf location matters too: the container should not block an exit, required access, or ventilation opening.
Test with the phone powered off. Place it in the cavity in the position you expect to use, then close the cover gently. The cover should settle without pressing on the screen, side buttons, or camera area. If you feel resistance or see the cover lift, stop and check for a tight spot rather than pushing it shut.
Then test retrieval. Lift the phone out with one hand if possible, without digging at the edges or tipping the book in a way that could drop the device. A small finger gap or fabric pull tab may help, as long as it does not press on the phone or prevent the cover from closing.
Choose a stable shelf or drawer surface. Check that opening the book does not knock nearby items over, and that the book does not sit near a heat-producing appliance. Do not put it in front of a doorway, an access point you need to reach, or an opening that supplies or removes air.
| Check | What to verify | If it fails |
|---|---|---|
| Length and width | At least 6 mm beyond the phone in each direction | Choose a larger cavity |
| Depth | At least 3 mm beyond phone thickness, plus lining | Use a deeper container |
| Cover | Closes without pressure or springing open | Remove a pressure point or change containers |
| Retrieval | Phone lifts out without force | Add a finger gap or reposition it |
| Shelf spot | Stable and clear of exits, access, and vents | Move the book |
Next step: Complete a close-and-reopen test before choosing the final shelf location.
Preparing the Hollow-Book Stash
Preparation means making a suitable container while leaving the building untouched. A purpose-made book safe avoids cutting pages yourself. If you modify a book, use one you own and remove material only from its pages. Do not cut into a wall, cabinet, framing, or any other part of the home.
A purpose-made book safe should still be checked against your phone’s measurements. Products can vary in cavity size, depth, and interior finish, so compare the listed dimensions with your device and case. If the product does not state usable cavity dimensions, measure the inside when it arrives rather than relying on the book’s outer size.
For a book you own, keep the work limited to the book itself:
- Mark the phone’s outline with the required clearance included.
- Make the cavity deep enough for the phone and any lining.
- Keep the edges smooth and remove loose scraps or dust.
- Check that no hard ridge or uneven surface presses on the screen.
- Avoid glue, lining, or inserts that cover buttons or catch on the phone.
Do not treat foam or felt as a way to make a cavity fit. Soft lining can compress, but it still takes up space. Measure its compressed thickness and include it in the cavity depth and width. If the phone only fits when the lining is crushed or the cover is forced down, the container is too small.
Next step: Before storing the phone, inspect the cavity for debris, rough edges, and any material that could catch on the device.
Verifying Safe Storage and Retrieval
Verification is a short repeatable check that confirms the phone is stored without pressure and can be removed when needed. A powered-off phone stored in a passive cavity has no prescribed ventilation rate. Charging is different: a closed, snug space can impede heat release, so keep the phone uncharged inside the book.
Follow this check each time you first set up the container:
- Power off the phone.
- Place it in the cavity and confirm that it sits flat.
- Close the cover without pressing down.
- Reopen the book and inspect for pressure marks, shifted lining, or loose debris.
- Lift the phone out, then return it and repeat the check.
Do not charge the phone in a closed book safe. Charging can generate heat, and a snug, insulated cavity may slow heat dissipation. Charge it outside the container on a hard, unobstructed surface, following the phone and charger instructions. Do not add an unlisted battery, charger, or wiring to the book.
A loose, non-powered book container is not an electrical installation. If you add powered equipment, follow its listing and instructions. In the United States, NEC 110.3(B) requires listed or labeled equipment to be installed and used in line with its instructions. For this simple storage use, the safer choice is to leave the book unpowered.
Next step: Keep the container passive and make charging a separate routine outside the book.
Practical Scenarios and Container Choices
The examples below are worked scenarios, not reports of named projects or measured product tests. They show how the same fit and safety checks apply in common homes. The right choice depends on the phone’s size, how often you need it, and whether the container stays in a stable, accessible spot.
Scenario: a phone stored on a family bookshelf. A homeowner wants to keep a spare phone out of sight among books. The family measures the device with its case, selects a book safe with enough cavity depth, and tests removal before placing it on a reachable shelf. Because children use the room, the homeowner also decides whether the phone should be stored somewhere children cannot mistake it for an ordinary book.
Scenario: a phone kept in a home office. A designer wants a clean desktop and chooses a modified book on a stable shelf. During the fit test, the phone’s camera bump catches on a shallow edge. The useful fix is a larger or deeper cavity, not pressing the cover closed. The phone remains powered off in storage and is charged elsewhere.
| Option | Best suited to | Main check |
|---|---|---|
| Purpose-made book safe | A quick, tidy container with less page work | Confirm usable cavity dimensions |
| Modified book you own | A specific book size or shelf look | Keep the work to the pages and check for debris |
| Open, ordinary book storage | Frequent access or a phone that needs charging | Keep the phone on a hard, clear surface |
These examples point to the same rule: choose a container for the measured device, then choose a location that suits how you use the phone. Concealment should not make retrieval awkward or turn a storage spot into a charging space.
Next step: Pick the option that meets the measurements and access needs, not just the one that looks most convincing on a shelf.
Frequently Asked Questions
These answers cover fit, preparation, and safe use of a hollow-book phone container. The key distinction is simple: the book can hide a powered-off phone as passive storage, but it is not a place to charge a device or install electrical parts. Measure first, test access, and keep the container clear of hazards.
How much larger should the cavity be than the phone?
Allow at least 6 mm more length and width than the measured phone and case. Allow at least 3 mm more depth than the phone’s thickness.
Should I measure the phone with its case on?
Yes, if you plan to store it in the case. Measure the exact setup you will use, including any camera bump that affects how the phone rests.
Can I store the phone while it is on?
For this setup, store it powered off. A passive cavity has no prescribed ventilation rate, but the phone should not be charging inside it.
Can I charge a phone inside a book safe?
No. Charge it outside the closed container, on a hard, unobstructed surface, and follow the phone and charger instructions.
Is felt or foam safe to add?
It can be used as a lining if it does not cover buttons or press on the phone. Include its compressed thickness in your cavity measurements.
How do I know if the cavity is too small?
If the phone catches, the lining must be crushed, or the cover presses on the screen or buttons, the cavity is too small. Do not force the cover closed.
Can I cut a hollow space into a wall or cabinet instead?
That is outside this project. Keep any book modification to a book you own, and do not cut building components to create a hiding space.
Does the book need ventilation holes?
Not for a powered-off phone in passive storage. Do not charge the phone in the closed cavity.
Where should I place the book?
Use a stable spot that does not block an exit, required access, or ventilation opening, and keep it away from heat-producing appliances.
Is a book safe childproof?
No. It is a concealment container, not a child-resistant lock. If a child should not reach the phone, choose storage that is secure for that purpose.
(This article was written by one of our staff writers, Michael Donovan. Visit our Meet the Team page.)
