How to Check a Phone When You Buy It

Phone inspection is a critical skill for professional phone resellers. Our phone buying checklist shows you how to check a used phone so you can avoid costly mistakes and maximize your return. Be sure to download the printable version to reference anywhere.
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1. Assess phone condition

Identify the phone’s cosmetic condition by visually inspecting it. Run diagnostics tests to determine its functional condition. Most Android phones have built-in diagnostics and iPhones feature battery diagnostics. For more detailed reports, you can install third-party phone diagnostics apps.

Built-in diagnostics

Enter these codes into the dialer to access diagnostics or browse to the specified location.

Android Diagnostics Menu: *#0*# Tests cameras, sensors, touch screen, power/volume buttons and more. On Samsung phones, you can test red, blue and green screen pixels, vibrating motor, speakers, touch screen, accelerometer and other sensors.

Usage Information Menu: *#*#4636#*#* Displays network and WiFi connection statistics, carrier information, phone number, app usage history and more.

iPhone Battery Performance: Browse to SETTINGS > BATTERY Displays information about battery performance, including maximum capacity, phone power requirements, peak performance and overall battery health.

Third-party phone diagnostics apps

Install these apps to run detailed diagnostics tests.

TestM (Android and iOS): Creates a complete phone condition report. Tests the touch screen, headphone jack, microphone, speakers, earpiece, accelerometer, gyroscope, compass, GPS, WiFi, Bluetooth, cellular connectivity, fingerprint sensor, hardware buttons, flash, proximity sensor, vibrating motor, charger and cameras.

Phone Doctor Plus (Android and iOS): Tests 30 different hardware components and sensors, including touch screen, multi-touch, headphone jack, speakers, microphone, call functions, accelerometer, gyroscope, proximity, display, compass, storage, memory, CPU, cameras, vibrating motor, flash, GPS, WiFi, Bluetooth, volume buttons, home button, temperature, humidity and more.

Phone Check and Test (Android): Runs a series of configurable tests and generates a report that includes device information like memory and storage plus test results for the battery, WiFi network, Bluetooth, NFC, microphone, earpiece, speakers, headphone jack, vibrating motor, display (dead pixels, color consistency, burn-in and bright pixels), touch screen, multi-touch, GPS, cameras, fingerprint sensor, accelerometer, step counter, proximity, CPU, temperature and more.

Use diagnostics results and visual inspection to assess phone condition according to the following:
  • NEW: Brand-new and in flawless condition with no signs of use. Includes all cables and accessories. Phone may be shrink wrapped.
  • LIKE NEW: Near-perfect condition with no blemishes or imperfections. Looks like it just came out of the box and includes all cables and accessories.
  • GOOD: Minimal wear from normal use, but functions as it should. Phone has no water damage but may have very light scratches or scuffs. Battery powers on and stays on.
  • FAIR: Phone is fully functional, though it may be fairly worn from consistent use. It may have scratches, dings and signs of normal wear and tear. Battery must power on and stay on.
  • POOR: Phone has heavy scratches or and shows evidence of heavy use. Screen may be cracked, scratched or gouged.
  • BROKEN: Phone has severe cosmetic damage, water damage, missing parts or broken glass. It may not turn on or have hardware and software issues. The phone might not charge or function at all.

2. Verify phone model, carrier and capacity

Use the settings menu to verify this information (typically under an “About” section). If the phone is broken and you can’t use the settings menu, locate its IMEI, ESN or MEID on the back of the case or in the SIM card try. Enter that number on a service like  SNDeepInfo to find its model and capacity.

3. Check if the phone is blacklisted

Make sure the phone isn’t blacklisted (reported lost or stolen) and that it’s not under a carrier contract or financing agreement. Enter the phone’s serial number, IMEI, ESN or MEID on a service like CheckESNFree. The service checks both the GSMA and NCIC databases to identify whether the phone is reported lost or stolen and if it’s under contract.
What is the phone blacklist and how does it work? We spoke with Shane from CheckESNFree to get the lowdown on the phone blacklist. There are two major blacklist databases: the GSMA database, which all major carriers report to, and the NCIC database, which is maintained by the FBI and used by law enforcement officials nationwide. Generally, phones end up on the blacklist if they’re reported lost or stolen by their owners, either to law enforcement or carriers. Most carriers will not activate phones that are on the blacklist. Despite these efforts, there are still flaws in the blacklist system. Though most carriers report lost or stolen phones immediately, there can still be delays between the time a phone is reported and when it propagates on the database so other carriers can view it. In addition, there are scammers who will sell their phones then report it stolen. This is usually done by someone who is attempting to get a replacement phone via insurance and still profit from the sale. To prevent such issues, it’s a good idea to verify the identity of anyone selling their phone. There is no automated way to verify phone ownership, so the best way to do this is to meet at their wireless carrier’s store. “I understand these measures are time-consuming, but they will help weed out the deceitful individuals who are more likely to have a stolen phone or pull a scam on you,” says Shane. “If a local seller isn’t willing to take these measures, then I’d recommend moving along and finding a device from someone who will.” If meeting at a carrier store isn’t an option, you can at least check the seller’s driver’s license and record their name, address and phone number so they can be contacted or reported if they make a fraudulent sale. That might not stop every phone selling scam (they could present a fake I.D., after all), but it will help protect you from the most obvious scammers.

4. Check if the phone is jailbroken or rooted

Jailbroken, or rooted, phones can contain spyware and other malicious software designed to steal data. On Android phones, you can use a root checker app to try to detect if a phone has been rooted. On iPhones, look for the presence of apps like Cydia, Icy and Installer, which are often installed when a phone is jailbroken. You should also check if default iPhone apps are installed. If any of the following apps are missing, the phone might be jailbroken: App Store, Calculator, Calendar, Clock, Camera, Contacts, iPod, iTunes, Mail, Maps, Messages, Notes, Phone, Photos, Safari, Settings, Stocks, Voice Memos, Weather and YouTube.

5. Disable security features

Disable security features like Find My iPhone Activation Lock, passwords, pin codes and biometric sensors so you can access the phone, reset it and activate it with a new carrier. After you buy the phone, you’ll need to wipe its data by resetting to factory settings before you resell it (or you can ask the seller to factory reset the phone once you’ve inspected it).

Disable Find My iPhone Activation Lock: Browse to SETTINGS > ICLOUD and select the iCloud name. Sign in and select DEVICES. Select the phone and choose REMOVE FROM ACCOUNT. Confirm.

Disable Screen Lock (iPhone): Browse to SETTINGS > TOUCH ID & PASSCODE. Select TURN PASSCODE OFF. Confirm. For biometric lock screens, browse to SETTINGS > TOUCH ID & PASSCODE (or FACE ID & PASSCODE). Turn off IPHONE UNLOCK.

Disable Find My Device (Android): Browse to SETTINGS > LOCK SCREEN AND SECURITY > FIND MY DEVICE. Turn it off.

Disable Screen Lock (Android): Browse to SETTINGS > SCREEN LOCK TYPE and choose NONE. Then, turn off any biometrics.

6. Remove any SIM cards and microSD cards

Ask the seller if they want these items. You can’t use the SIM card, and a microSD card isn’t likely to add value on resale.

7. Check the resale value of the phone

Use a free service like to see how much the phone is worth in its current condition. Use this information to make an offer that yields a healthy profit margin.

8. Pay for the phone, then resell it for a profit

Pay the seller, then use to instantly resell the phone for a profit. Flipsy doesn’t buy phones; instead, our free service compares real-time buyback offers so you can see who is paying the most for nearly any phone in any condition. Flipsy’s Trust Verified Stores offer free shipping, instant sales and payments submitted within three days of the buyer receiving the phone. If you have multiple phones, you can use the bulk selling feature to sell them all at once. If you’re a professional phone reseller looking for more phones to flip, Flipsy Local can help you find them.

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