Your iPhone’s battery health is “good” at 80% or above. Apple designs iPhone batteries to retain about 80% of their original capacity after 500 full charge cycles (or 1,000 cycles for iPhone 15 and later), which typically takes about two years of normal daily use. Below 80%, you may notice shorter runtime between charges but your phone isn’t damaged, and replacement is a choice, not an emergency.

What Is iPhone Battery Health?

Battery health is a percentage that shows how much charge your iPhone’s battery can currently hold, compared to when it was brand new. A battery at 100% health holds a full charge exactly as it did on day one. A battery at 85% health can only hold 85% of that original capacity  so you’ll charge more often, even though nothing is technically broken.

This number lives in Settings > Battery > Battery Health & Charging, and it’s built into every iPhone 6 and later running iOS 11.3 or newer.

It’s worth separating two ideas that often get blurred together:

• Battery life: how long your phone runs on a single charge, on a given day.
• Battery lifespan: how long the battery itself lasts before it needs replacing.

Battery health is really a window into lifespan. It tells you how much of the battery’s total usable life has already been spent.

How to Check Your iPhone’s Battery Health

Checking it takes about 15 seconds and needs no extra apps:

• Open Settings.
• Tap Battery.
• Tap Battery Health & Charging.
• Look at “Maximum Capacity.” That percentage is your battery health.

While you’re there, note whether you see a message under Peak Performance Capability. If it says your battery is “supporting normal peak performance,” you’re fine. If it flags a “significantly degraded” battery, that’s worth reading closely more on that below.

What Percentage Is Considered Good?

There’s no single universal cutoff, but here’s a practical way to read the number:

Battery Health	What It Generally Means
95–100%	Essentially new. No noticeable difference from day one.
85–94%	Normal wear for a phone that’s roughly a year or two old. Still fully reliable.
80–84%	Apple’s baseline “normal” threshold. You may notice slightly faster drain by evening, but this is expected, not faulty.
Below 80%	Below Apple’s designed retention target. Some people notice real day-to-day impact here; others don’t, depending on usage. This is the point where it’s worth considering not rushing into  a replacement.

For most day-to-day users, anything above 80% is functionally fine. The 80% line isn’t a “broken” threshold  it’s simply the point Apple engineers the battery to still reliably clear after hundreds of charge cycles.

Maximum Capacity vs. Peak Performance Capability  What’s the Difference?

This is where a lot of explainers get muddy, because there are actually two separate battery metrics on that Battery Health screen, and they measure different things.

Maximum Capacity is the percentage most people mean when they say “battery health” it’s about how much energy the battery can store.

Peak Performance Capability is about how much power the battery can deliver instantly, even if it’s fully charged. As lithium-ion batteries age, their internal resistance (impedance) rises. According to Apple’s official battery documentation, when a battery has higher impedance, it can’t deliver power as smoothly, and voltage can drop more sharply under demandThis is a characteristic of battery chemistry common to all lithium-ion batteries in the industry. If that dip goes below what the phone’s components need, iOS may apply performance management subtle, temporary slowdowns (like longer app launch times or dimmer backlighting) designed to prevent an unexpected shutdown rather than let the phone crash mid-useEffects can include longer app launch times, lower frame rates while scrolling, and gradual frame-rate reductions in some apps. 

So it’s possible to have decent Maximum Capacity but still see a performance-management notice, especially after an unexpected shutdown. The two numbers tell you different things, and checking both gives you the full picture.

Why Does Battery Health Drop? (The Science, Simply)

Every rechargeable lithium-ion battery is a consumable part; it’s designed to wear down with use, the same way brake pads or tires do. Two forces drive that wear:

• Charge cycles. One full cycle happens when you’ve used an amount of power equal to 100% of your battery’s capacity, not necessarily in one sitting. Charging from 50% to 100% twice adds up to one cycle.
• Chemical aging. Time, heat, and how the battery is used all affect its internal chemistry, independent of cycle count alone.

Here’s a detail almost no other guide on this topic mentions clearly: Apple doesn’t use the same design target for every generation. According to Apple’s own support documentation, batteries in iPhone 14 models and earlier are designed to retain 80 percent of their original capacity at 500 complete charge cycles under ideal conditions, while batteries in iPhone 15 models are designed to retain 80 percent of their original capacity at 1000 complete charge cycles under ideal conditions. In plain terms: if you own an iPhone 15 or newer, Apple engineered your battery to hold up roughly twice as long, cycle-for-cycle, as an iPhone 14 or earlier model. That’s a meaningful reason two people with “the same” charging habits can see very different battery health curves depending on which iPhone they own. 

How to Slow Battery Degradation

None of these habits will reverse wear that’s already happened  chemical aging isn’t undone  but they genuinely slow future wear:

• Keep your charge between 20% and 80% for daily use. Full discharges and constant 100% top-offs both add extra stress compared to shallower charge cycles.
• Turn on Optimized Battery Charging (Settings > Battery > Battery Health & Charging). It learns your routine and delays the final push to 100% until closer to when you’ll actually unplug, reducing time spent fully charged.
• Avoid heat. Apple’s own guidance is specific here: it’s especially important to avoid exposing your device to ambient temperatures higher than 95° F (35° C), which can permanently damage battery capacity. Leaving your phone on a dashboard or charging it under a pillow both count. 
• Take the case off while charging if your phone runs hot  some cases trap heat that would otherwise dissipate.
• Update iOS regularly. Apple periodically ships refinements to charging and performance-management algorithms.
• Store an unused iPhone at around 50% charge, not full or empty, if you’re putting it away for months.

When Should You Replace Your iPhone Battery?

Think of this as a spectrum, not a switch:

• Above 85%: No action needed.
• 80–85%: Keep an eye on it. If your daily usage still comfortably lasts you a full day, there’s no rush.
• Below 80% and you’re noticing it: This is the reasonable window to start considering replacement especially if you see unexpected shutdowns, sluggish performance, or you’re charging more than once a day just to get through routine use.
• “Significantly degraded” warning shown: Apple explicitly recommends service at this point.Your battery’s health is significantly degraded, and an Apple Authorized Service Provider can replace the battery to restore full performance and capacity but Apple also notes this message doesn’t indicate a safety issue and the phone remains usable in the meantime. 

One more thing worth knowing: if you ever see an “Unable to Verify This iPhone Has a Genuine Apple Battery” message, it usually means the battery was replaced by someone other than Apple or an Apple Authorized Service Provider. It doesn’t necessarily mean the battery is bad but Apple notes the health data shown may not be fully accurate in that case.

iPhone Battery Replacement Cost in Canada

If you’re leaning toward a replacement, cost is usually the deciding factor. A few things shape the price:

• In-warranty or AppleCare+: If your iPhone is still under its standard one-year warranty and the battery is defective, service is included. If you have AppleCare+, battery replacement is also covered at no extra charge once Maximum Capacity drops below 80%.
• Out-of-warranty, through Apple: Pricing is tiered by model complexity. As of Apple’s most recent U.S. pricing (which Canadian pricing typically mirrors closely, converted and adjusted for local tax), standard iPhone models have generally run in the US99range,PromodelsaroundUS119–129, with older/simpler models sometimes lower. Because Apple periodically revises these fees and CAD figures aren’t always published on the same page as USD ones, confirm your exact price for your model at  before booking  treat any number here as an estimate, not a quote.
• Third-party and independent repair shops: Often cheaper than Apple, and can be a reasonable option  just weigh it against the fact that a non-Apple battery may trigger the “unable to verify genuine battery” message and could affect resale value or future service eligibility.
• Booking: In Canada, replacements can typically be arranged through the Apple Support app, an Apple Store Genius Bar appointment, or by mail-in service Apple will inspect the device to confirm the final fee before charging you.

Because pricing changes and varies by exact model and region within Canada, we’d recommend the writer/publisher of this piece pull current CAD figures directly from Apple.ca at time of publishing rather than relying on the estimates above  flagging this explicitly per the brand’s fact-checking process.

Conclusion

Understanding iPhone battery health helps you monitor battery performance and recognize when the battery may need attention. Checking Settings > Battery > Battery Health & Charging lets you view maximum capacity and important battery information. Good charging habits, avoiding excessive heat, and keeping your iPhone updated can help maintain battery performance, while a significantly degraded battery may indicate that replacement is worth considering.

FAQs

Is 80% battery health bad?

No. 80% is the threshold Apple designs iPhone batteries to retain after hundreds of charge cycles; it’s expected wear, not a defect. Most people don’t notice a meaningful difference in daily use until health drops several points lower.

Can iPhone battery health be improved once it drops?

Not chemically  degraded battery capacity can’t be reversed through software or settings. What can help is making sure the reported percentage is accurate (via iOS updates) and slowing further decline with better charging habits going forward.

Does fast charging hurt iPhone battery health?

Fast charging generates more heat than standard charging, and heat is one of the main accelerants of battery aging. Occasional fast charging is fine; relying on it constantly, especially in warm conditions, can contribute to faster wear over time.

How many charge cycles does an iPhone battery last?

Apple designs iPhone 14 and earlier batteries to retain 80% capacity at 500 complete charge cycles, and iPhone 15 and later batteries to retain 80% capacity at 1,000 complete charge cycles under ideal conditions.

How much does an iPhone battery replacement cost in Canada?

It depends on your model and whether you have AppleCare+. Apple’s standard-model out-of-warranty fees have generally sat around the US$99 mark, with Pro models higher  but exact current CAD pricing should be confirmed directly at support.apple.com/en-ca, since fees are updated periodically.

Does AppleCare+ cover battery replacement?

Yes  under AppleCare+, Apple will replace your battery at no extra cost once Maximum Capacity falls below 80%, for the duration of your coverage.