Your phone battery needs replacing when it no longer holds a charge through a normal day, drains faster than it used to, or swells inside the phone
Most smartphone batteries start to degrade after 500 to 1,000 full charge cycles — roughly two to three years of normal use. You'll notice this as a gradual decline: the phone dies at 20 percent battery, takes longer to charge, or shuts down unexpectedly even when the battery indicator shows 30 percent remaining. These are signs the battery's chemical capacity has worn down and replacement is the practical fix.
A swollen battery is a safety issue that requires when ready replacement. If your phone feels thicker than it used to, the screen is lifting away from the frame, or you see a bulge on the back, stop using it and take it to a repair shop or manufacturer. A swollen battery can overheat or catch fire.
Cold weather can mask a failing battery — your phone may work fine in a warm room but die when ready in winter. This doesn't mean the battery is fine; it means the chemical reaction inside slows in cold. Once you're back indoors, the problem returns.
Key Takeaways
- A battery that dies at 20 or 30 percent, or drains noticeably faster than it did six months ago, has reached the end of its useful life.
- Unexpected shutdowns, slow charging, or the phone feeling warm during normal use are all signs of battery degradation.
- A visibly swollen battery is a safety hazard and should be replaced when ready by a professional.
- Battery replacement typically costs between $50 and $150 depending on the phone model and where you have it done.
- Most phones can have the battery replaced without replacing the entire device, though some models make this harder than others.
How to tell if your battery is actually failing
The most reliable sign is the battery health percentage available in your phone's settings. On iPhone, go to Settings > Battery > Battery Health & Charging; on Android, the location varies by manufacturer, but look in Settings > Battery or Settings > Device Care. A battery at 80 percent health or below is noticeably degraded. At 50 percent or lower, replacement is overdue.
If your phone shuts down at 30 percent and won't turn back on until you plug it in, the battery can no longer deliver the power the phone needs, even though it still holds some charge. This is different from the phone straightforward running out of power — it's a sign the battery's internal resistance has increased too much.
Slow charging is another clue. If your phone used to charge from empty to full in 45 minutes and now takes two hours, the battery is degrading. A truly slow charger or a damaged cable can cause the same symptom, so test with a different cable and charger first.
When to replace the battery versus replacing the phone
Battery replacement makes sense if the phone is less than four years old, has no other hardware damage, and you're otherwise happy with it. A new battery often costs $60 to $120 and restores the phone to near-original performance. If the phone is five years old or older, the processor and other components are also aging, and a new battery may only buy you another year or two.
If the phone has a cracked screen, water damage, or a broken charging port in addition to battery problems, repair costs add up quickly. In that case, replacement may be more practical than stacking repairs.
Some phones are harder to repair than others. iPhones and Samsung Galaxy phones can be serviced at official stores or certified third-party shops. Older or less common models may have fewer repair options, which can drive up the cost or make replacement the only realistic choice.
Where to get a battery replacement
The manufacturer's official service center — Apple Store, Samsung Service Center, or equivalent — is the safest choice. They use genuine parts, warranty the work, and have the tools for phones with glued-together cases. The cost is usually $69 to $99 for iPhones and $50 to $100 for Samsung phones, though prices vary by region and model.
Authorized third-party repair shops (look for the manufacturer's certification badge) offer the same parts and warranty at similar prices, often with faster appointments. You can find them through the manufacturer's website or by searching "[your phone brand] authorized repair near me."
Independent repair shops are cheaper — often $40 to $70 — but quality varies. Ask whether they use genuine or aftermarket batteries; aftermarket batteries are cheaper but may not last as long or hold as much charge. Check reviews on Google or Yelp before you go, and ask about their warranty on the replacement battery itself.
Avoid extremely cheap replacements (under $30) from unknown vendors. A battery that costs $15 to manufacture is unlikely to perform well or last long, and a poor replacement can damage the phone's charging circuit.
What happens during a battery replacement
The technician will back up your data (or ask you to do it beforehand), power off the phone, and open the case. On most phones this takes 30 minutes to an hour. They'll disconnect the old battery, remove it carefully, install the new one, and test it before closing the phone back up. Your data stays on the phone — this is not a factory reset.
After replacement, the new battery will show 100 percent health in your settings. It will take a few charge cycles (usually three to five) to calibrate properly, so don't be alarmed if the percentage jumps around slightly in the first week.
If you had the battery replaced at an official service center, you'll receive a warranty on the replacement — typically one year. Keep your receipt. If the new battery fails within that period, they'll replace it again at no cost.
How to extend your current battery's life
Keep your phone between 20 and 80 percent charged as much as possible. Charging from 0 to 100 percent every day stresses the battery more than topping up from 30 to 80 percent. If you use your phone heavily, charge it twice a day rather than once.
Avoid heat. Don't leave your phone in direct sunlight, in a hot car, or running demanding apps (games, video recording) for long stretches. Heat accelerates battery degradation. If your phone feels warm during normal use, close background apps and let it cool down.
Use low-power mode or battery saver mode when the charge drops below 30 percent. This reduces processor speed and background activity, which slows the drain and reduces stress on the battery.
Turn off location, Bluetooth, and Wi-Fi when you're not using them. These drain the battery faster and, over time, contribute to degradation through repeated deep discharges.
Cost and timeline for replacement
Official service centers typically complete battery replacements within one to three business days, though some locations offer same-day service if you arrive early. Third-party shops often have faster turnaround — sometimes same-day — because they handle higher volume.
The total cost depends on the phone model and where you go. Here's a rough range:
| Service Type | Typical Cost | Warranty |
|---|---|---|
| Official manufacturer service | $69–$120 | 1 year on battery |
| Authorized third-party shop | $60–$110 | 6 months to 1 year |
| Independent repair shop | $40–$80 | 3 to 6 months (varies) |
If you're out of warranty and the phone is still under AppleCare+ or a manufacturer protection plan, the battery replacement may be covered or discounted. Check your coverage before you book.
Frequently Asked Questions
Can I replace the battery myself?
You can on some phones, but it's risky. iPhones and many Samsung models have glued cases that require heat tools to open safely. If you crack the screen or damage the charging port while opening it, the repair cost jumps to $200 or more. Unless you've done phone repairs before, professional replacement is worth the extra cost.
Will a new battery make my old phone feel new again?
A new battery will restore all-day battery life and eliminate unexpected shutdowns, but it won't speed up the processor or improve the camera. If the phone feels slow, that's a separate issue related to age, not the battery. A new battery is the right fix only if battery life is the problem.
How long does a replacement battery last?
A genuine replacement battery will last two to three years under normal use, the same as the original. Aftermarket batteries may last 18 to 24 months. The lifespan depends on how you charge it — keeping it between 20 and 80 percent extends it significantly.
What should I do if my phone battery is swollen?
Stop using the phone when ready and take it to a repair shop or manufacturer service center as soon as possible. A swollen battery is a fire hazard. Don't try to open the phone yourself or leave it plugged in. Tell the shop the battery is swollen so they can handle it safely.
Is it worth replacing the battery in a five-year-old phone?
It depends on the phone's condition and your needs. If everything else works and you're happy with it, a $70 battery replacement buys another year or two of use. If the screen is cracked, the charging port is loose, or you need more storage or a better camera, replacement is probably more practical.