How to Check iPhone Battery Health Before Selling in 2026

Checking your iPhone's battery health takes about 10 seconds, and it's one of the most important things to know before selling your device. The battery health percentage directly affects what buyers are willing to pay, and knowing your number upfront helps you get an accurate quote.

Step-by-Step Instructions

1. Open the Settings app on your iPhone.
2. Scroll down and tap Battery.
3. Tap Battery Health & Charging (on iOS 16 and later) or Battery Health (on iOS 14-15).
4. Look at the Maximum Capacity percentage.

That percentage tells you how much charge your battery currently holds compared to when it was brand new. A brand-new iPhone starts at 100%. Over time, as you charge and discharge the battery through normal use, this number decreases.

What You'll See on the Screen

• Maximum Capacity: This is the key number. It tells you your battery's current capacity as a percentage of its original capacity.
• Peak Performance Capability: This tells you whether your iPhone is running at full speed or if Apple's Performance Management has kicked in (more on this below).
• Optimized Battery Charging: A feature that slows charging past 80% to reduce battery wear. Keep this enabled.
• Charging Optimization: On newer iOS versions, you may see an 80% charge limit option that further reduces battery degradation.

What If You Can't Find Battery Health?

Battery Health is available on iPhone 6 and later running iOS 11.3 or newer. If you don't see it:

• Make sure your iPhone is updated to the latest version of iOS (Settings > General > Software Update).
• If you have an iPhone 5s or earlier, the feature isn't available. These very old models have minimal resale value regardless.

Knowing your battery health before getting a quote means you can select the right condition when pricing your phone on GadgetRenu's iPhone page. This leads to an accurate quote that won't need to be revised after inspection.

The battery health percentage is simple on the surface — 100% is new, lower is worse — but understanding what the numbers actually mean helps you contextualize your phone's value.

The Chemistry Behind the Number

All iPhones use lithium-ion batteries, which degrade with every charge cycle. A "charge cycle" is one full discharge of the battery's capacity — whether that's going from 100% to 0% in one session or from 100% to 50% twice. Apple rates iPhone batteries to retain 80% of their original capacity after 500 complete charge cycles (800 cycles for iPhone 15 and later).

What Different Percentages Mean

95-100%: Near-new condition. Your battery is barely worn. This is typical for phones less than 6 months old with moderate use. No impact on resale value or performance.

90-94%: Excellent. Normal wear for a phone that's 6-18 months old. You'll notice slightly less screen-on time compared to when the phone was new, but the difference is minor. No meaningful impact on resale value.

85-89%: Good. Typical for a phone that's 18-30 months old. Daily battery life is noticeably shorter — you might need to charge mid-afternoon instead of lasting all day. Minimal impact on resale value — most buyback companies consider this acceptable.

80-84%: Fair. This is where things start to matter for resale. Your phone's battery life is noticeably shorter than new, and you're approaching the threshold where Apple's Performance Management may engage. Expect 5-10% reduction in trade-in offers.

Below 80%: This is Apple's official replacement threshold. When your battery drops below 80%, you'll see a "Service" message in Battery Health, and Performance Management actively throttles your phone's processor to prevent unexpected shutdowns. Expect 10-15% reduction in trade-in offers.

The 80% Threshold Explained

Why does 80% matter so much? When battery capacity drops below 80%, two things happen:

1. Performance Management activates. Apple throttles the processor speed to prevent the degraded battery from causing unexpected shutdowns. Your phone literally runs slower.

2. Daily usability suffers. A battery at 78% capacity means your phone effectively has 78% of its original battery life. If your iPhone originally lasted 10 hours, it now lasts about 7.8 hours — and in cold weather or with heavy use, even less.

For buyers and refurbishers, a phone below 80% needs a battery replacement ($89-119 at Apple) before it can be resold as a quality refurbished device. That replacement cost is reflected in the lower offer you'll receive.

GadgetRenu tests battery health as part of their inspection process and factors it directly into every quote. There are no hidden deductions — if your battery affects your price, you'll know why.

Let's put specific numbers on the battery health impact so you can calculate what your phone is worth.

Price Impact by Battery Health Range

Using an iPhone 15 Pro (256GB, unlocked) as an example — worth approximately $391 in excellent condition with good battery health:

For a higher-value phone like the iPhone 16 Pro Max ($633 excellent condition), the dollar impact is proportionally larger:

Should You Replace the Battery Before Selling?

Apple charges $89 for battery replacement on most iPhone models and $119 for Pro Max models. The math:

• If your battery is at 78% and a replacement would add $40-60 to your resale value, don't replace it — you'd spend $89 to gain $40-60.
• If your battery is at 72% and a replacement would add $80-100 to your resale value, it's borderline — the savings barely cover the cost.

In nearly every case, it's more cost-effective to sell the phone as-is and let the professional refurbisher handle the battery replacement at their wholesale cost. GadgetRenu replaces batteries in-house at their New Jersey facility for a fraction of what Apple charges consumers.

Battery Health vs. Other Value Factors

To put battery health in perspective, here's how it compares to other value factors for the same iPhone 15 Pro:

• Model/generation: Biggest factor. The difference between an iPhone 15 Pro and iPhone 14 Pro is ~$100.
• Storage capacity: Second biggest. 256GB vs 128GB can mean $50-80 more.
• Cosmetic condition: Cracked screen reduces value by 40-50% ($150-190).
• Carrier lock status: Locked phones lose 10-15% ($40-60).
• Battery health: Below 80% costs 10-15% ($40-60).

Battery health matters, but it's not the dominant factor unless it's severely degraded. Don't let a battery at 83% stop you from selling — the phone is still worth very close to full value. See how much your iPhone is worth for complete pricing.

Samsung doesn't make battery health as easily accessible as Apple does, but there are several ways to check your Galaxy phone's battery condition before selling.

Method 1: Samsung Members App (Recommended)

This is the most reliable method for Samsung Galaxy phones:

1. Open the Samsung Members app (pre-installed on all Galaxy phones; download from Galaxy Store if missing).
2. Tap Get Help (or the support tab at the bottom).
3. Tap Interactive checks or Phone diagnostics.
4. Select Battery or Battery Status.
5. The app will display your battery's health status — typically as "Good," "Normal," or "Weak."

Samsung Members doesn't give you an exact percentage like Apple does, which is frustrating for sellers who want to know precisely where they stand. However, the categories map roughly to:

• Good/Normal: Battery is above ~80% capacity. No significant impact on resale value.
• Weak: Battery has degraded below approximately 80%. This will affect your trade-in offer.

Method 2: Dial Code (Some Models)

On some Samsung Galaxy phones, you can dial ##4636## to access a hidden testing menu that shows battery health information. This doesn't work on all models and carriers, but it's worth trying. Look for "Battery health" or "Battery level" in the menu that appears.

Method 3: Settings (Galaxy S24 and Later)

Starting with the Galaxy S24 series and One UI 6.1, Samsung added battery health to the main Settings:

1. Open Settings > Battery.
2. Look for Battery health or Battery diagnostics.
3. You'll see the remaining capacity as a percentage or a health rating.

Method 4: Third-Party Apps

Apps like AccuBattery can estimate your battery's health over time by measuring actual charge capacity versus design capacity. Install the app, charge your phone fully a few times, and it will estimate your battery health as a percentage. This is less precise than Apple's built-in reporting but gives you a reasonable estimate.

Samsung Battery Lifecycle

Samsung rates its batteries for approximately 800 charge cycles before reaching 80% capacity (for Galaxy S23 and later; older models were rated for about 500 cycles). In practice, most Samsung phones maintain 85%+ battery health for the first 18-24 months of normal use.

If you're selling your Samsung Galaxy to GadgetRenu, they'll test the battery as part of their standard inspection. Knowing your approximate battery health beforehand helps you select the right condition and get an accurate quote.

Google Pixel phones have a built-in battery health feature that's straightforward to access, especially on newer models.

Pixel 6 and Later (Recommended Method)

1. Open Settings.
2. Tap Battery.
3. Tap Battery usage or look for Battery health information.
4. On Pixel 8 and later running Android 14+, you'll see a battery health percentage similar to iPhone's Maximum Capacity.

Pixel 4-5 Series

Older Pixels don't have a native battery health display in Settings. Your options:

1. Dial ##4636## to access the testing menu and look for battery information.
2. Use AccuBattery or a similar third-party app to estimate battery health based on charge measurements.
3. Check the Battery section in Settings for general information about battery usage patterns, though this won't show a health percentage.

Google's Battery Health Guarantee

Google has stated that Pixel 7 and later batteries are designed to retain at least 80% capacity after 800 charge cycles. For the Pixel 8 series, the guarantee extends to approximately 1,000 cycles. This is competitive with both Apple and Samsung's battery longevity claims.

Impact on Pixel Resale Value

Battery health affects Pixel trade-in values similarly to how it affects iPhones and Samsung phones:

• Above 85%: No meaningful impact on resale offers.
• 80-84%: Expect 5-10% reduction.
• Below 80%: Expect 10-15% reduction.

The dollar amounts are smaller for Pixels because their overall resale values are lower than iPhones, but the percentage impact is comparable.

GadgetRenu accepts Google Pixel phones of all generations and conditions. Get your Pixel quote to see what your device is worth, battery health included.

If you're planning to sell your phone in the next few months, there are practical steps you can take right now to preserve your battery health and maximize your payout.

1. Enable Optimized Charging

iPhone: Settings > Battery > Battery Health & Charging > Optimized Battery Charging. This learns your daily routine and delays charging past 80% until you need it, reducing stress on the battery.

Samsung: Settings > Battery > Battery Protection. On newer models, you can set a charge limit of 80% or 85%.

Pixel: Settings > Battery > Adaptive charging. This slows overnight charging to reduce wear.

2. Avoid Extreme Heat

Heat is the enemy of lithium-ion batteries. Every time your phone gets uncomfortably warm — from direct sunlight, gaming while charging, or sitting on a car dashboard — the battery degrades faster.

Practical tips:

• Don't leave your phone in direct sunlight or in a hot car.
• Remove your phone case while charging if your phone tends to get warm.
• Avoid intensive gaming or video recording while plugged in.

3. Avoid Full Discharges

Lithium-ion batteries last longest when kept between 20% and 80% charge. Regularly draining to 0% puts extra stress on the battery chemistry. If you can avoid letting your phone die completely, your battery will last longer.

4. Use the Right Charger

Apple and Samsung design their fast charging to be safe, but using non-certified third-party chargers with unknown power profiles can generate more heat than necessary. Stick with your original charger or a reputable third-party option (Anker, Belkin, etc.).

5. Don't Obsess Over It

Here's the reality check: battery health degradation follows a curve that's mostly determined by time and usage patterns. These tips can help at the margins — preserving maybe 2-5% more health over a year compared to careless charging habits. But they won't turn an old battery into a new one.

The most impactful thing you can do for your phone's resale value is sell it sooner rather than later. A phone with 90% battery health today is worth more than the same phone with 85% battery health six months from now, even if those tips preserved a few percentage points.

Lock in today's value by getting a quote from GadgetRenu. Their iPhone page, Samsung page, and other device pages give instant quotes that hold for 14 days — plenty of time to ship from anywhere in the country to their New Jersey facility.

This is a legitimate fear, and it comes up frequently in online discussions about selling phones. Let's address it directly.

Where the Fear Comes From

Some buyback companies have a business model that relies on quoting a high price to get you to ship your phone, then revising the offer downward based on "inspection results." Battery health is one of the easiest things to cite as a reason for a lower offer because:

• Most sellers don't check their battery health before shipping.
• Battery health is a technical measurement that's hard for the average person to verify.
• There's no widely-known standard for what constitutes "acceptable" battery health.

A dishonest company could claim your battery is at 75% when it's actually at 85%, use that as justification for a $50 price cut, and most sellers would accept it because they can't prove otherwise.

How to Protect Yourself

Step 1: Screenshot your battery health before shipping. This is the single most important thing you can do. Go to Settings > Battery > Battery Health, take a screenshot, and save it. If any buyer disputes your battery health, you have documentation.

Step 2: Note your battery health in the transaction. When getting your quote, select the condition that matches your actual battery health. If GadgetRenu asks about battery condition and yours is at 88%, say so. This creates a record that matches your screenshot.

Step 3: Choose a buyback company with transparent grading. GadgetRenu's approach is to explain exactly how your phone was graded after inspection. If your battery health is 85%, that's what they'll report. If it's different from what you described, they'll tell you the number they measured and explain the impact on your quote. You can then compare it to your screenshot.

How GadgetRenu Measures Battery Health

GadgetRenu uses professional diagnostic tools — the same type used by Apple Authorized Service Providers — to measure battery health during inspection. These tools read the battery's actual cycle count and capacity from the battery management chip, providing an accurate measurement that can't be manipulated.

The measurement happens at their R2-certified facility in New Jersey, and the result is documented as part of the device inspection record. If there's a discrepancy between what you reported and what they measure, they'll contact you with the details before processing payment.

The Bottom Line

Battery health concerns are valid, but they're manageable. Screenshot your battery health, be honest in your description, and choose a reputable buyer. GadgetRenu's transparent process means there are no surprises — and if you disagree with their assessment, they'll return your phone for free.

For more on getting the best price for your phone, check out our guides: How Much Is My iPhone Worth? and How to Get the Most Money for Your Used MacBook.

What battery health percentage is considered bad for selling a phone?

Below 80% is the threshold where battery health starts to meaningfully affect trade-in values, typically reducing offers by 10-15%. This is Apple's official replacement threshold and the point at which Performance Management throttles your iPhone's processor. Above 85%, battery health has minimal or no impact on offers from most buyback companies, including GadgetRenu. Between 80-85% is a gray area where some buyers may apply a small discount.

Can battery health go back up?

No. Battery health reflects the chemical degradation of the lithium-ion cells, which is a one-way process. The number can only go down over time. Occasionally, you might see a small fluctuation (e.g., 87% jumping to 88%) due to calibration changes in how iOS measures capacity, but this doesn't represent an actual improvement in the battery's condition. The only way to restore battery health is to physically replace the battery.

How many charge cycles does an iPhone battery last?

Apple designs iPhone batteries to retain 80% capacity after 500 complete charge cycles (iPhone 14 and earlier) or 800 cycles (iPhone 15 and later). In real-world use, most people complete one full cycle per day, which means the battery should last about 1.5-2 years before reaching 80%. Heavy users who charge twice daily may hit the threshold sooner, while light users may maintain 85%+ for three or more years.

Does fast charging damage battery health?

Apple's and Samsung's built-in fast charging systems are designed to be safe for the battery. They charge quickly to about 80%, then slow down to reduce heat and stress. This is why the last 20% takes noticeably longer than the first 80%. Using the manufacturer's fast charger or a certified third-party charger (MFi-certified for Apple, Samsung-approved for Galaxy) will not meaningfully degrade your battery faster than standard charging.

Should I charge my phone to 100% or stop at 80% to preserve battery health?

For maximum battery longevity, keeping your charge between 20-80% is ideal. Both Apple (with Optimized Battery Charging) and Samsung (with Battery Protection) offer built-in features that automatically manage this. If you're selling your phone within the next few months, enabling these features can preserve 1-3% more battery health compared to regularly charging to 100%. On iPhone, go to Settings > Battery > Battery Health & Charging. On Samsung, go to Settings > Battery > Battery Protection. For more tips on maximizing your phone's value before selling, visit GadgetRenu's iPhone selling page or Samsung selling page.