How Long Can You Leave Your iPhone Flashlight On?

Most iPhones come with a rear-facing flashlight that we've come to take for granted. You can light things up with a simple press of a button — or even easier, turn on your iPhone's flashlight without touching it. Maybe you're jogging at night and the park lights go out, or maybe you're hunting for a misplaced Lego brick under the couch. But these are instances where you turn off the flashlight immediately after using it. In case you were wondering whether you can use the iPhone flashlight continuously for several hours without turning it off, there are both advantages and limitations. The good news is that the iPhone flashlight can stay on for several hours. The bad news is that there are too many factors at play to predict exactly how long, including the battery charge, how you use your handset while the flashlight is on, the age of the device, and the environment.

Safety equipment manufacturer Petzl ran experiments to determine how much energy a smartphone uses while powering the flashlight. The company left a smartphone flashlight on for three hours, using the device minimally during the test. The test found that the battery dropped from 65% to 19%. That's about 15% per hour or 1% every five minutes. Petzl argues that users should consider dedicated illumination hardware, like its own headlamps, instead of smartphones.

Petzl did not say whether it used an iPhone or Android device for the experiment. However, the company mentioned that phone flashlights can emit light at only 30 to 60 lumens, compared to headlamps that start at 300 lumens. Petzl also noted that flashlights on iPhone 17 Pro models emit about 30 lumens, while the iPhone Air and iPhone 17 offer 40 lumens. Samsung Galaxy flagships feature flashlights that can offer 40 to 60 lumens.

iPhone users who spend time outdoors in low-lit environments and those interested in how long their phone can function as a flashlight can run their own experiments to determine how long their handset will work as a flashlight. That's what I did with my iPhone 14 Pro. I recharged it to 100%, turned on the flashlight, and set a timer for one hour to see how much battery the flashlight would use. I ran the experiment during the day, without using the handset. The screen was off, and the phone was connected to cellular networks and Wi-Fi. That means the handset would have delivered notifications while it was working as a flashlight.

The battery was at 94% when the timer rang, indicating my iPhone flashlight would consume about 6% of battery life every hour. In theory, that would give me 16.6 hours of continuous flashlight use. To get that sort of experience in an emergency, you'd need to have a full battery charge, which may not be possible. Also, you would have to avoid using your handset for any purposes, like making calls and texting others, including emergency services you might need to contact. Add navigation, and battery drain increases.

The more you use the handset while the flashlight is on, the faster the battery depletes. Also, the environment can impact the battery performance. I ran the test indoors, during the day, at temperatures of around 22 degrees Celsius (71.6 degrees Fahrenheit). The phone wasn't hot to the touch afterward, though prolonged flashlight use may impact the phone's temperature. Finally, keep in mind that older handsets, like my iPhone 14 Pro, do not offer the same battery life as newer devices, as battery health degrades over time.

Apple doesn't offer iPhone battery life estimates for continuous flashlight use. That's a fringe case most people will not experience. A MacRumors forum user ran a similar experiment in 2024, discovering that the iPhone 15 Pro Max would consume between 3% and 4% of its battery capacity during a 30-minute test. The handset could be used as a flashlight for 12.5 hours, assuming a consistent 4% drain per 30 minutes of use. My iPhone flashlight test and the MacRumors experiment both show better figures than Petzl's findings. But given that the iPhone should be used for communication and navigation purposes in emergencies, you should limit the flashlight use. Instead of keeping the light on continuously, only turn it on when you absolutely have to.

Also, instead of using the iPhone as a flashlight, you may consider buying a dedicated light source, with Amazon offering many dedicated flashlight options. Another alternative iPhone users can consider is keeping an old or secondary Android phone that features a powerful flashlight. Some of these devices also work as power banks, and they can recharge your primary handset. This scenario could be useful for people who camp in remote areas or those who live in areas prone to natural disasters, like floods, fires, and storms, that can lead to power outages. A jogger running at night can use the iPhone flashlight for several hours before the battery runs out. The same goes for searching for that particular Lego brick under the couch, though the process won't take hours of your time.