What Should I Check Before Buying a Second-Hand Phone?

The useful way to approach a used-phone purchase is to separate it into two questions: can you legally take control of this device, and does the device work as represented? Those are different checks. A clean screen does not prove a clean ownership history.

How do I check whether a used phone has been stolen?

Check the device's IMEI against an appropriate handset-status service, ask the seller for proof of ownership, and walk away if the ownership or status check cannot be completed before payment. The Federal Communications Commission identifies an IMEI, MEID, or ESN as a device's unique identification number; it is generally available in settings or on a label under the battery.

For an in-person purchase, compare the IMEI shown by the phone with the number the seller gives you. The Australian Mobile Telecommunications Association says an IMEI is a unique 15-digit number and can generally be displayed by dialing *#06#. That comparison is simple, but it matters: it helps ensure that the number checked belongs to the phone in front of you.

An IMEI check is necessary but not conclusive. According to the Australian Mobile Telecommunications Association, its status result only reflects phones reported at the time of the inquiry, and there can be a 72-hour lag before a lost or stolen report shows as blocked. It also advises buyers to check a phone's status before a second-hand purchase; a carrier will not unblock a device reported lost or stolen and blocklisted.

That caveat changes the process. An unblocked lookup does not make a seller trustworthy; it only answers one narrow question at one moment. Request proof of ownership, retain the listing and payment record, and do not accept a rushed explanation for why the seller cannot demonstrate the device. Consumer Reports specifically notes that an unpaid-device carrier lock can be hidden behind a working, undamaged-looking phone.

Can I check an IMEI before buying a second-hand phone?

Yes, you can check an IMEI before buying, but use the result as a current status check and not as a substitute for verifying ownership and network access. The FCC explains that IMEI, MEID, and ESN numbers uniquely identify mobile devices, while AMTA provides a handset-status lookup for Australian networks.

Ask for the IMEI before meeting if the seller is willing, then repeat the check with the phone present. If the seller refuses to show the identifier or the displayed number does not match the number used for the lookup, stop there. Public data does not provide a universal promise that a device will never later be reported lost, stolen, or blocked, so the seller's documentation still matters.

Also distinguish an IMEI status check from a carrier-lock check. An IMEI can be currently unblocked while a phone remains restricted to a carrier. On an iPhone, Apple says to open Settings, General, and About: “No SIM restrictions” beside Carrier Lock means it is unlocked, while a carrier name means it is restricted to that carrier.

For iPhones, ownership needs one final check that the IMEI cannot answer. Apple's Activation Lock guidance says that a device displaying “iPhone Locked to Owner” is Activation Locked and should not be accepted. If a passcode screen or Home Screen appears, have the seller completely erase the device; during setup, it should not request the previous owner's Apple Account information. The Hello screen is the point Apple identifies as ready for the buyer.

How much battery health is acceptable on a used iPhone?

There is no single battery-health percentage that makes every used iPhone acceptable; use the displayed maximum capacity, any battery messages, the model's design target, price, and your own charging test together. Apple defines maximum capacity as capacity relative to when the battery was new, and chemical aging reduces time between charges.

Apple says iPhone 14 models and earlier are designed to retain 80% of original capacity after 500 complete charge cycles under ideal conditions. For iPhone 15 models, the stated design target is 80% after 1,000 complete charge cycles under ideal conditions. Those figures are useful reference points, not a guarantee about a particular phone's remaining day-to-day use.

Open Settings, Battery, then Battery Health, or Battery Health & Charging on iOS 16.1 and later. Review maximum capacity and any important battery messages. Apple also says an aged battery can provide insufficient peak power, increasing the likelihood of unexpected shutdowns and potentially triggering performance management.

Battery information should not be considered alone. Apple's preowned-iPhone checklist says to inspect the display, sides, back, and charging connector for damage or debris, and not to buy an iPhone if it will not charge during testing. In Settings, General, About, review Parts and Service History on compatible iPhones running iOS 15.2 or later. An “Unknown” part can indicate a nongenuine, previously used, incomplete, or malfunctioning replacement part.

Test the screen, buttons, speakers, charging port, and the functions the seller will allow you to inspect while together. Consumer Reports says certified refurbishment programs may run dozens of diagnostics covering speakers, screens, buttons, and charging ports. The same source offers a useful warning: outward appearance cannot establish a phone's health by itself.

What is the safest way to complete the purchase?

Complete the checks before payment, keep a record of the listing and transaction, and favor a documented return policy when one is available. Consumer Reports advises against refurbished devices without a warranty and recommends a seller that allows at least one month for returns. It reports that Apple, Google, Samsung, and Back Market offer one-year refurbished-phone warranties, while Amazon, Best Buy, and Walmart are reported to offer 90-day warranties.

A certified refurbished option does not erase the need to inspect the phone, but it changes the risk calculation: diagnostics, warranty coverage, and a return route are documented. A private seller may offer none of those things. The practical conclusion is not that every private listing is bad; it is that you should demand a more complete inspection when the transaction provides less recourse.

Keep the process boring. Verify the identifier, confirm network and ownership status, inspect the physical device, test charging, and preserve the paperwork. That is a more reliable standard than a persuasive message or a low asking price. For another practical safety checklist, see What Is a Safe At-Home Balance-Training Plan to Reduce Fall Risk?.