iPhone 8 Battery Replacement: Cost & DIY Guide
A new iPhone 8 battery costs about $15 to $35 in DIY parts, roughly $50 to $85 at a local repair shop, or $89 through Apple. The job is genuinely DIY-friendly: the iPhone 8 opens from the front like every iPhone since the 5, and a first-timer can swap the cell in about 30 to 45 minutes with a basic toolkit.
Launched in 2017, the iPhone 8 is now closing in on a decade of service, and almost every unit still running is on its original cell. That small 1,821 mAh battery was never generous to begin with, so once it degrades, the drop in runtime is dramatic. The good news is that this is one of the cheapest and most satisfying repairs you can do yourself, and it keeps a perfectly capable phone out of the landfill.
How to check your iPhone 8 battery health
Before you buy anything, confirm the battery is actually the problem. On the iPhone 8, go to Settings > Battery > Battery Health & Charging. Apple introduced this screen with iOS 11.3, and the iPhone 8 supports it fully.
Look at two numbers. Maximum Capacity shows how much charge the battery holds versus when it was new. On a phone this old, anything from the 70s down into the 60s is common, and Apple considers a battery "consumed" once it drops below 80%. The Peak Performance Capability line is the other tell: if it reads "your battery's health is significantly degraded" or mentions an unexpected shutdown, iOS is already throttling your processor to keep the phone from dying under load. A fresh cell removes that throttling and the phone feels noticeably quicker.
Signs your iPhone 8 battery is failing
The classic symptom people search for is an iPhone 8 battery draining fast even when the phone sits idle. Other warning signs include:
- The phone shuts down suddenly at 30%, 20%, or even in cold weather while showing charge left.
- Sluggish performance, stuttering animations, or apps that feel throttled.
- An iPhone 8 battery not charging past a certain point, or charging extremely slowly.
- The phone runs hot during light tasks.
- Maximum Capacity has fallen below 80%.
Safety note on swelling: if the screen starts lifting away from the frame, the back glass bulges, or there is a visible gap around the edges, stop using the phone. A swollen lithium-ion cell is a fire and rupture hazard. Do not puncture it, do not press it flat, and never charge it. Replace a swollen battery promptly and recycle the old one at an e-waste drop-off rather than tossing it in household trash.
iPhone 8 battery replacement cost
Here is what you can expect to pay in 2026 across the three common routes:
| Option | 2026 price | What you get |
|---|---|---|
| Apple (out of warranty) | ~$89 | Genuine cell, done at a store or by mail |
| Local repair shop | $50 - $85 | Labor included, usually same day |
| DIY replacement | $15 - $35 | Battery, adhesive, and tools; your labor |
The iPhone 8 battery replacement cost gap is stark: doing it yourself is often a fifth of Apple's price. Buying at wholesale volume drops the per-unit parts cost even further, which is why repair shops and refurbishers source their cells the same way. You can compare current pricing across our replacement battery collection.
The exact replacement battery you need
The iPhone 8 uses a 1,821 mAh lithium-ion battery. Make sure the model you own is a standard iPhone 8 and not an 8 Plus, which uses a physically larger and higher-capacity cell that will not fit. The iPhone 8 is sold under model numbers A1863, A1905, and A1906 depending on region and carrier; you can confirm yours under Settings > General > About.
When you shop for an iPhone 8 OEM battery or a quality aftermarket equivalent, look for a zero-cycle cell (never previously charged) that matches the 1,821 mAh rating. Cheap, under-rated cells are the number one reason a "new" battery underperforms within weeks. Our zero-cycle replacement cells are graded for full rated capacity so you get the runtime you paid for.
A quiet advantage of the iPhone 8
Unlike the iPhone XS, XR, and everything newer, the iPhone 8 predates Apple's battery serialization. That means a third-party battery generally will not trigger the "Unable to verify this iPhone has a genuine Apple battery" lockout, and Battery Health will usually keep reporting a percentage normally. It is one of the easiest iPhones to service without software headaches.
How to replace an iPhone 8 battery yourself
Here is the overview of how to replace an iPhone 8 battery. You will need a P2 pentalobe driver, a Y000 tripoint and Phillips driver, a suction cup, a plastic pick, tweezers, and a set of pull-tab adhesive strips.
- Power down and remove the two pentalobe screws beside the charging port.
- Lift the screen with a suction cup and pick, opening it from the bottom edge. The display hinges on the right side; open it like a book but do not yank the display flex cables.
- Disconnect the battery first. Remove the metal bracket over the connectors and unplug the battery before touching anything else. This is the single most important safety step.
- Release the adhesive pull-tabs. The battery is held by two or three stretch-release strips at the base. Pull each one slowly and straight out until it releases. If a tab snaps, apply gentle heat and use a plastic card, never a metal pry tool, against the cell.
- Seat the new battery, apply fresh adhesive, reconnect, and reassemble in reverse order.
Honest difficulty rating: 3 out of 5. The iPhone 8 is beginner-approachable, and the biggest risk is a torn adhesive strip rather than any fragile component. Take your time on the pull-tabs and keep track of the differently-sized screws, and the whole job is comfortable for a careful first-timer.
After the swap
Once the phone is back together, do a full calibration cycle: charge to 100%, then let it run down to a normal daily low and charge back up. This helps the battery gauge report accurate figures. Because the iPhone 8 has no battery authentication lock, Battery Health should show your new capacity without a warning; if it briefly reads "Service," a charge cycle usually clears it. If you ever see a persistent genuine-parts message on a newer iPhone you service later, that is normal for XS-and-up models and does not affect performance.
Repair vs. upgrade: the green math
A $15 to $35 battery brings an iPhone 8 back to all-day runtime. A comparable replacement phone, even a used one, runs many times that. More importantly, manufacturing a new smartphone generates the vast majority of its lifetime carbon footprint before it ever leaves the box. Swapping a single cell keeps a fully working device in service and keeps its embedded emissions and rare-earth materials out of the waste stream. For a phone that still handles calls, messaging, banking, and everyday apps without complaint, replacing the battery is the obvious call. That is the whole idea behind repair over replacement: keep good hardware alive.
Ready to get started? Grab the parts from our battery collection, and if you have a different device in the drawer, our battery replacement by model guide covers dozens of iPhones, Galaxy, and Pixel phones.
FAQ
How much does an iPhone 8 battery replacement cost?
In 2026, expect about $15 to $35 for DIY parts, $50 to $85 at an independent repair shop, or roughly $89 through Apple. Doing it yourself is by far the cheapest route.
How do I replace an iPhone 8 battery myself?
Power off, remove the two pentalobe screws, lift the screen from the bottom, disconnect the battery connector first, release the adhesive pull-tabs, seat the new 1,821 mAh cell with fresh adhesive, and reassemble. It takes 30 to 45 minutes with a basic toolkit.
Why is my iPhone 8 battery draining fast?
After years of use, a degraded cell loses its ability to hold charge and iOS may also be throttling performance. Check Settings > Battery > Battery Health; a Maximum Capacity below 80% is the usual cause and a replacement fixes it.
My iPhone 8 battery is not charging. Do I need a new battery?
Not always. First clean the charging port and try a known-good cable and adapter. If it still will not charge, or only charges intermittently, an aged or failing battery is the likely culprit and should be replaced.
What size battery does the iPhone 8 use?
The iPhone 8 uses a 1,821 mAh lithium-ion battery. Note that the iPhone 8 Plus uses a larger cell that is not interchangeable, so confirm you have the standard iPhone 8 (model A1863, A1905, or A1906).
Will a third-party iPhone 8 battery show a warning?
Generally no. The iPhone 8 predates Apple's battery serialization, so a quality aftermarket cell usually will not trigger the "genuine battery" warning, and Battery Health keeps reporting normally.