How to Check Used iPhone Battery Health Before You Buy

Quick answer

Before buying a used iPhone, open Settings > Battery > Battery Health & Charging to check Maximum Capacity and Cycle Count. Aim for 85% or higher and under 500 cycles for a phone that still has useful life. If the numbers are lower or the seller won't let you check, walk away or budget for a battery replacement.

Why battery health matters more than cosmetic grade

A used iPhone can look pristine but still have a worn battery that forces you to charge twice a day. Battery health affects performance, resale value, and how soon you'll pay for a replacement. For refurbished iPhones, the battery is often the only part that degrades with use, so it deserves a closer look than scratches or dents.

What the numbers mean: Maximum Capacity and Cycle Count

Maximum Capacity is the battery's current capacity relative to when it was new. A reading of 100% means it holds a full charge; 80% means it holds 80% of its original capacity. Apple considers a battery degraded when it falls below 80%, and that's when you'll notice shorter runtime and possible performance management. Cycle Count tracks how many full charge-discharge cycles the battery has completed. One cycle equals using 100% of capacity, not one plug-in. Most iPhone batteries are designed to retain up to 80% capacity at 500 cycles. A phone with 300 cycles and 92% capacity is in better shape than one with 600 cycles and 85%.

Where to find battery health on different iPhone models

On iPhone 14 Plus, iPhone 15, and iPhone 16 Pro, go to Settings > Battery > Battery Health & Charging. You'll see Maximum Capacity and, on iPhone 15 and later, Cycle Count. If you're buying a used iPhone from a third-party seller, ask them to show you this screen before you meet. If they refuse or the screen shows 'Unknown Part' or a service message, the battery may have been replaced with a non-genuine part, which can affect performance and future service options.

How to verify battery health during a meetup

When you meet a seller, don't rely on screenshots. Open Settings yourself and navigate to Battery Health. Check that the phone is not plugged in and that the percentage shown matches the battery icon. Then test real-world drain: play a 4K video at 50% brightness for 10 minutes and note the drop. A healthy battery should lose only a few percent. Also check for unexpected shutdowns by looking at Settings > Privacy & Security > Analytics & Improvements > Analytics Data for panic logs. If you see multiple panic-full entries, the battery or other hardware may have issues.

What to do if battery health is low

If Maximum Capacity is below 85% or cycle count is over 500, factor in the cost of a replacement. Apple's official battery service pricing varies by model and region, so check Apple's website for current rates. Third-party replacements are cheaper but may show a warning and lack features like Battery Health reporting. For a refurbished iPhone, a low battery isn't always a dealbreaker—just make sure the price reflects it. If you're buying from a reputable refurbisher, ask whether the battery has been tested or replaced. A generic box is common with refurbished phones, so don't expect original packaging unless stated.

Used iPhone buying checklist: battery and beyond

Battery health is just one part of the used iPhone buying checklist. Also check the display for dead pixels or burn-in, test all buttons and cameras, verify Face ID or Touch ID, and confirm the phone is not iCloud locked. Run a quick diagnostic by dialing *#06# to see the IMEI and compare it to the settings. If the phone has been opened, check for loose screws or gaps around the screen. A phone with great battery health but a cracked screen is still a poor buy.

Step-by-step: How to check used iPhone battery health

1. Open Settings and go to Battery: Tap Settings > Battery > Battery Health & Charging. On iPhone 15 and later, you'll also see Cycle Count. If the seller won't let you navigate to this screen, that's a red flag. Checkpoint: You should see Maximum Capacity and, on newer models, Cycle Count without any service warnings.
2. Read Maximum Capacity and Cycle Count: Note the percentage and cycle number. A capacity of 90% or higher with under 300 cycles is excellent. 85–89% with 300–500 cycles is average. Below 85% or over 500 cycles means the battery is aging. Checkpoint: If capacity is below 80%, the battery is degraded and will likely need replacement soon.
3. Check for service messages or unknown parts: Look for messages like 'Unable to verify this iPhone has a genuine Apple battery' or 'Unknown Part'. These indicate a non-genuine or poorly installed battery, which can affect performance and future repairs. Checkpoint: A genuine battery will show no warning. If you see one, ask for proof of replacement or negotiate the price down.
4. Test real-world battery drain: Unplug the phone, set brightness to 50%, and play a 10-minute video. Note the percentage drop. A healthy battery should lose 2–5%. Also check for unexpected shutdowns in Analytics Data. Checkpoint: If the phone drops more than 10% in 10 minutes or shows panic logs, the battery or hardware may be faulty.
5. Decide based on cost of replacement: If the battery needs replacement, look up Apple's current out-of-warranty battery service price for that model. Add that to the purchase price and compare with other options. A third-party replacement is cheaper but may show a warning. Next step: If the total cost still saves you money versus a newer model, it can be a good deal. Otherwise, keep looking.

Examples from our current stock

• iPhone 14 Plus – 128GB – Red – Grade B: iPhone 14 Plus – 128GB – Red – Grade B, comes with a generic box. Grade B may have cosmetic wear, but you can still check battery health in Settings before buying. A generic box means no original packaging, so focus on the phone's condition and battery readings.
• iPhone 15 – 128GB – Green – Grade A+ Pristine: iPhone 15 – 128GB – Green – Grade A+ Pristine, comes with a generic box. Grade A+ indicates pristine cosmetic condition, but battery health can still vary. Always verify Maximum Capacity and Cycle Count, as even pristine phones can have worn batteries.
• iPhone 16 Pro – 128GB – Desert Titanium – Grade A+ Pristine: iPhone 16 Pro – 128GB – Desert Titanium – Grade A+ Pristine, comes with a generic box. A newer model like the iPhone 16 Pro may have lower cycle counts, but it's still worth checking battery health. A generic box means the original accessories aren't included, so factor that into the price.