How to Test a Used Laptop Before You Buy It

Before you meet

Ask for the exact model number, processor, RAM, storage and the original purchase date. Search the model to learn its common problems — some models are known for weak hinges or failing batteries. Ask the seller to have the laptop fully charged, and plan to test it for at least 15 minutes.

Physical check

• Hinges: open and close the lid. It should hold its angle without wobbling or creaking.
• Case: look for cracks near the hinges and corners, and a bulging bottom or a touchpad that sits higher than usual — signs of a swollen battery. Don’t buy a laptop with a swollen battery.
• Ports: plug your USB stick into every port and the charger into the laptop. Check that it actually charges.
• Screws: stripped or missing screws suggest it has been opened and repaired.

Screen: dead pixels and backlight

Open the Dead Pixel Test in full screen. It cycles through solid colors: a dead pixel shows as a black dot on bright colors, a stuck pixel as a colored dot that never changes. On the black screen, look at the edges for light leaking in (backlight bleed) and for uneven patches. Tilt the screen and check that colors don’t shift too much.

Keyboard and touchpad

Open the Keyboard Tester and press every key once. Each key lights up when it registers, so a dead key is obvious. Watch for keys that register twice from one press (chatter) or keep firing after you let go (stuck) — the tester flags both. Try the function keys, the arrow keys and the keyboard backlight.

For the touchpad and mouse buttons, the Click Speed Test checks left and right clicks, double-click and scrolling. Also try two-finger scroll and pinch-to-zoom in a web page.

Battery health

Battery wear is the most common hidden cost.

• Windows: open Command Prompt and run powercfg /batteryreport. Open the HTML report it saves and compare “Full charge capacity” with “Design capacity”. Below about 80% means noticeably shorter battery life.
• macOS: System Settings → Battery → the info button next to Battery Health shows the maximum capacity; System Information → Power shows the cycle count.

Check the real specs

Make sure what you’re told matches what’s inside.

• Windows: Settings → System → About shows the processor and RAM; Settings → System → Storage shows the drive size.
• macOS: Apple menu → About This Mac.

Also confirm Windows is activated (Settings → System → Activation).

Camera, microphone, speakers and Wi-Fi

Run the Webcam Test and the Mic Test, and record a few seconds to play back through the speakers — listen for crackling at higher volume. Connect to your phone’s hotspot to confirm Wi-Fi works and load a few pages.

Account locks: the deal-breaker

A laptop still tied to the seller’s account can become useless after you pay.

• Mac: Activation Lock must be off — ask the seller to sign out of their Apple ID and turn off Find My while you watch. Ideally, see the Mac erased and restarted to the setup screen.
• Windows: there should be no BIOS or firmware password, and the seller should reset the PC or remove their account.
• Business laptops: a message about the device being managed by an organization means it is enrolled in company management. Walk away unless the seller can prove it was released.

Quick checklist

1. Hinges, case, no swollen battery.
2. All ports and charging work.
3. No dead pixels or heavy backlight bleed.
4. Every key and the touchpad work.
5. Battery health above about 80%.
6. Specs match the listing; Windows activated.
7. Camera, mic, speakers and Wi-Fi work.
8. Seller’s accounts removed, no firmware password or management lock.