Guides

Buying a used phone: how do you check it properly?

swissmax editorial team November 9, 2026

Always check a used phone in person before you pay: the IMEI (*#06#) must match the original box and the receipt, and Find My or the Google account must be signed out and the phone reset in front of you. Then test the battery, screen, cameras and a call with your own SIM card. If there is no proof of ownership or a lock stays active, walk away.

Key points

Match the IMEI: dial *#06# and compare with the settings, box and receipt.
Remove the locks: Activation Lock (iPhone) and Google account protection (Android) must be off before you pay.
Check the battery: below 80% capacity, budget for a replacement, often CHF 80 to 150 depending on the model and repair shop.
Test on the spot: meet in a public place, test for 15 to 20 minutes, then pay in cash or by TWINT.
Check where it came from: under Art. 934 of the Swiss Civil Code, the owner of a stolen phone can reclaim it for up to five years after the theft.

1. Before you meet: check the listing and the seller

In the chat, ask for the model and storage, purchase date, receipt and original box, any previous repairs and a screenshot of the battery health. On recent iPhones, the Parts and Service History (Settings > General > About) shows whether the screen, battery or camera has been replaced.

Warning signs: a very low price, pressure, shipping only against payment up front, or a push to move to WhatsApp straight away. Our guide to spotting classified-ad scams covers more patterns.

2. Check the IMEI and ownership

The IMEI is the 15-digit number that identifies a phone on the mobile network. Here is how to check it:

Dial *#06# in the Phone app. Dual-SIM or eSIM phones show two numbers.
Compare it with the settings (iPhone: General > About, Android: About phone), the original box and the receipt.
If anything does not match or there is no proof at all: do not buy. A receipt in someone else's name needs a believable explanation.

Depending on the operator, a phone reported as stolen can be blocked on the network using its IMEI, even weeks after you bought it.

3. Have Activation Lock and the Google account removed

This is the key step: an active lock stops you setting the phone up after a reset, and only the previous owner can remove it.

iPhone and iPad

The seller opens Settings > [their name] and signs out with their password. This turns off Find My and Activation Lock.
Then: Settings > General > Transfer or Reset iPhone > Erase All Content and Settings.
The phone restarts on "Hello". Set it up with your SIM and Wi-Fi as far as activation: if it asks for the previous owner's Apple Account, do not buy.
If a "Remote Management" notice appears, the phone belongs to a company or school. Do not buy it.

Android

The seller removes their Google account under Settings > Accounts and, on Samsung phones, the Samsung account too.
They then do a factory reset from the settings.
On restart, there must be no prompt to verify a previously used Google account. Otherwise Factory Reset Protection (FRP) is active.

Do not accept "I'll unlock it later". Pay only once the phone is reset and set up for you.

4. Test the battery, screen and for water damage

Battery: on an iPhone, Settings > Battery > Battery Health. Apple says a battery is designed to keep around 80% of its capacity after 500 charge cycles, or 1,000 cycles from iPhone 15 onwards. From iPhone 15, the cycle count is under Settings > General > About. On Android, some manufacturers show battery health in the settings or in a diagnostics app.
Screen: on a white and a grey image, look for marks, burn-in and dead pixels; drag an icon across the screen to find dead touch areas.
Cameras and unlocking: test every lens, the flash and focus, and set up Face ID or the fingerprint sensor again.
Calls and ports: make a call with your SIM, check the microphone with a voice memo, and test the speakers, Wi-Fi, Bluetooth, charging and buttons.
Water damage: on many iPhones, an indicator in the SIM tray shows liquid contact (red instead of white or silver). Also look for fogging under the camera lens, corrosion in the charging port and muffled sound. An IP rating does not mean the phone has never been wet.

5. Carrier lock: rare in Switzerland, but test it

Phones sold in Switzerland today are mostly not SIM-locked, but some prepaid offers, imported phones or older contract phones can be. The test: insert your SIM or activate your eSIM and make a call.

6. Stolen phones: the legal risk

Under Art. 934 of the Swiss Civil Code, the owner of a stolen phone can reclaim it from any buyer for five years from the theft, even one acting in good faith. They only have to refund the price you paid if you bought it at a public auction, at a market or from a dealer in goods of that kind, so as a rule not in a private sale. Anyone who knows or must assume that a phone is stolen also commits the offence of handling stolen goods under Art. 160 of the Swiss Criminal Code.

Typical signs: a very low price, no receipt, a locked phone, evasive answers about where it came from. Swiss Crime Prevention (SCP) has more tips on safe online trading at skppsc.ch.

7. Payment and warranty

Pay once every test is passed, in cash or by TWINT at the handover: never up front to strangers, no gift cards, no crypto. Private sellers often exclude the warranty ("sold as seen"), but under Art. 199 of the Code of Obligations the exclusion does not cover defects the seller fraudulently concealed. Put the condition, known faults, IMEI and price in writing. More in our guide to safe handovers and payment.

What a used phone typically costs in 2026

Rough guide values for flagship models from the major brands, depending on storage, condition and battery. iPhones usually hold their value better than many Android phones:

Under 1 year old: often 65 to 80% of the new price, towards the top with remaining warranty.
1 to 2 years: often 50 to 65% of the new price.
3 to 4 years: typically CHF 200 to 450.
5 years and older: often CHF 80 to 200, with older mid-range phones frequently under CHF 100.

A weak battery, scratches or a non-original screen justify a lower price. See our guide to pricing second-hand items.

How swissmax helps

Price check: where there are enough similar listings, swissmax shows the usual price range of the last six months. A guide, not a valuation.
Chat warnings: if someone writes a phone number, a link, an IBAN or a typical scam phrase, you both see a warning.
ID checked: the listing shows whether the seller has had their official ID checked. If they add a phone number, only signed-in users can reveal it.
Deals: where offered, you agree price, place and time, pick a safe public meeting spot and review each other afterwards. If something goes wrong, open a dispute on the deal page.
Report and follow: the "Report" button alerts our team; a search alert tells you when a matching phone appears in Phones & Tablets.

See also our safety tips and the FAQ. More devices are in Electronics, smartwatches in Wearables & Smartwatches.

Frequently asked questions

How do I find a phone's IMEI?

Dial *#06# in the Phone app. The number must match the settings, the original box and the receipt.

Can I buy a phone without a receipt?

Yes, but it is riskier: there is no proof of ownership, and any manufacturer's warranty is harder to use. At least ask for the original box with a matching IMEI and a written confirmation with name, date, IMEI and price.

What happens if the phone turns out to be stolen?

The owner can reclaim it for up to five years after the theft (Art. 934 Civil Code), after a private sale usually without refunding you. Depending on the operator, the phone can also be blocked via its IMEI. Report it to the police and keep all messages and receipts to claim your money back from the seller.

Is a phone with a worn battery worth buying?

Often yes, if the price is right. Below 80% capacity, budget for a battery replacement (often CHF 80 to 150) and negotiate accordingly. Also check that the model still gets security updates, or banking apps and TWINT become a risk.

Last updated: November 2026. Prices are guide values, and the legal information is not a substitute for legal advice.