Is your laptop dying after two hours when it used to last all day? Laptop batteries are consumables: they lose capacity with every charge cycle. A replacement can make a three- or four-year-old laptop feel useful again for a fraction of the cost of a new one. This guide shows how to check battery health, when to replace, how to choose a battery and how to make the new one last longer.
Safety first: if your battery is swollen — the trackpad lifts, the case bulges or the laptop rocks on a table — stop using and charging it immediately. Don’t press, puncture or try to flatten it. Have it removed by a professional repair shop or the manufacturer.
Step 1: Check battery health
| System | How |
|---|---|
| macOS | System Settings → Battery → Battery Health (the info button shows maximum capacity). For cycle count: System Information → Power. |
| Windows | Open Command Prompt and run powercfg /batteryreport. Compare “Design capacity” with “Full charge capacity”. |
| Manufacturer apps | Lenovo Vantage, Dell Power Manager/SupportAssist, HP Support Assistant, MyASUS show battery condition. |
Step 2: Decide if it’s time
- Below ~80% of design capacity and battery life no longer fits your day → worth replacing.
- Sudden shutdowns at 20–30% → the battery can’t deliver peak power.
- System warning (“Service recommended” on Mac, battery warnings on Windows).
- Swelling → replace immediately (see above).
If the laptop is also slow, consider whether other upgrades (an SSD, more RAM if upgradeable) plus a battery make it worth keeping — or whether it’s time for a new machine. See best laptops under $1,000.
Step 3: Choose a replacement
| Option | Pros | Cons |
|---|---|---|
| Manufacturer service | Genuine part, warranty, installed safely | Most expensive |
| Authorized repair shop | Genuine or quality parts, professional installation | Cost varies |
| Third-party battery (DIY) | Cheapest | Quality varies widely; risk during installation |
When buying a third-party battery:
- Match the part number printed on your old battery (not just the laptop model name).
- Match voltage and connector; capacity can be similar or slightly higher.
- Prefer sellers with clear warranties, safety certifications and many recent reviews.
- Be wary of unrealistic capacity claims in the same physical size.
DIY tips
- Look up a guide for your exact model (iFixit has many step-by-step guides).
- Shut down fully and disconnect the charger; disconnect the battery connector before other work.
- Use plastic tools near batteries — never metal pry tools.
- Glued-in batteries (common in thin laptops) are much harder; consider professional service.
- Recycle the old battery at an electronics or battery drop-off point — never in household trash.
Make the new battery last
- Limit charging to ~80% when mostly plugged in: Lenovo Conservation Mode, ASUS Battery Health Charging, Dell Power Manager, HP Battery Care, Samsung Battery Protection. On Mac, keep Optimized Battery Charging on.
- Avoid heat: don’t use the laptop on beds or pillows; heat ages batteries fastest.
- Use a quality charger — see our USB-C charger guide.
- Don’t store it at 0% or 100% for long periods; around 50% is best.
Need power on the go while you wait for a replacement? See the best power banks for laptops.