Leaving Phone Flashlight On: Bad?

Here’s everything about leaving your phone flashlight on being bad:

In general, leaving the flashlight on, even for hours at a time, will not harm the flashlight itself or the phone.

The flashlight can slowly contribute to battery drain, so if you have to do it for a long time, plug in the phone.

In the long run, the flashlight will not cause any serious harm to the phone.

If you want to learn all about what happens when you keep your phone flashlight on, then this article is for you.

Keep reading!

Leaving Phone Flashlight On: Bad? (It's Safe)

What Does the Flashlight Do to the Phone? (4 Things)

Smartphone in a female hand at a concert.

If you really want to understand why you can or can’t safely leave the flashlight turned on, you need to know more about how it really functions. 

Obviously, it’s just a light.

It’s usually the same light that is used to create a flash for photos when you use the phone’s camera.

It can also be initiated when you try to do a video recording in the dark.

None of that is what really matters.

The flashlight on your phone is an LED light.

While LEDs have been around for a while now, they’re still relative newcomers in the world of lighting. 

Because of that, a lot of people still don’t have a strong idea of how LEDs work and what they do to a phone.

So, let’s get into it.

#1 How LEDs Work

perosnal computer gaming station with bright neon led lights

LED stands for light-emitting diode, and this describes the mechanism that actually creates light.

LEDs accomplish this through a process known as electroluminescence.

This is a complicated word that means the LEDs turn electricity into light.

How can they do that?

It has to do with the microscopic structure of an LED.

The last word, diode, refers to the basic design of the device. 

Diodes are made from semiconductors, and they have a specific shape.

In particular, an LED is made of two different kinds of semiconductors that join at a specific point.

One side has extra microscopic holes or gaps.

On the other side, there is an abundance of electrons.

When you run a current through the junction, electrons are enticed to jump from one side to the other.

The jumping electrons emit electromagnetic energy as a result of making the jump.

With an LED, the diode uses materials where the jumping electrons will emit electromagnetic energy of specific frequencies.

This is what you end up seeing as the emitted light.

In other words, the diode design forces electrons to emit the desired type of energy, and that ultimately produces light that you can see.

Because the diodes can be designed with high precision, they can emit light of any color.

Your phone’s flashlight will emit white light because it is better for general visibility.

Meanwhile, the phone’s screen uses the same technological concept to produce red, blue, or green light in very small pixels.

That is how images are formed on the screen.

So, knowing all of that, how does an LED light impact your phone?

#2 Battery Drain

woman smiling while using smartphone at night at home.

The light on your phone will use additional battery power.

That much is certain, but it probably doesn’t use nearly as much power as you might expect.

The vast majority of other functions of the phone consume a lot more power.

Here’s a bit of perspective.

If you don’t use the phone for anything else, you can leave your light on for hours at a time.

In fact, the average fully charged phone battery can keep the flashlight shining for 10 hours of consecutive use.

That’s how little power is drained by the light, and it’s because LED lights are so efficient.

Talking on the phone, playing games, scrolling social media, listening to music, or just downloading information all use more battery power than the flashlight.

But, it’s still important to understand that the flashlight contributes to battery drain, and that’s because of the battery life cycle.

Phone batteries all wear down over time.

Every time you charge the battery, you shorten its life by a little bit.

So, using the battery more causes you to recharge it more, and that will drain the battery and end its life sooner rather than later.

The flashlight is a small contributor, but it’s worth considering.

If you left the flashlight on nonstop, it would ultimately hasten the end of your battery’s life. 

It would take months to lead to a meaningful change in battery health, but it can eventually happen.

So, leaving the light on is fine for the battery, but if you literally never turn the light off, it can be a problem.


#3 Strain on the Light

Mobile phone in women's hand, pink neon light in the background

Forgetting batteries for a bit, you have to wonder how long the flashlight can work before it burns out the light.

All lights eventually burn out, and you don’t want to be without the flashlight on your phone.

This isn’t really a problem.

The kinds of LEDs used for a phone flashlight can last for tens of thousands of hours of use.

You are not going to burn it out very easily.

In fact, most phones completely die of old age before the LED wears out.

Here’s another way to think about it.

LEDs form the backlight for the phone screen.

How many hours have you had that screen active?

Have you ever really been worried about the backlight burning out?

Is it something that happens often?

The flashlight LEDs are made from the same technology and have a similar lifespan.

#4 Heat

Man using mobile phone at night on street

The LED might not cause much strain on the battery, and the light itself can last a long time.

But, it can still make the phone hot, right?

You don’t want a burning hot light in the palm of your hand if you can help it.

Once again, LED technology makes this a non-problem.

LEDs run very cool compared to other lights and electronic devices. 

A typical LED bulb that has been on for hours is safe to touch with your bare hands (depending on the light being used).

This is because LEDs don’t produce light by making metal really hot. 

Instead, they directly convert electricity into light.

The only heat comes from the resistance in the wire.

Over time, that does generate warmth, but it pales in comparison to the old incandescent bulbs you might be thinking of.

The LEDs on your phone flashlight are not high-powered lights.

They draw less than a watt of power, and they don’t face very much resistance from the phone circuit.

These lights are much cooler than even the LEDs you might put in a ceiling fan light.

You can test this yourself.

Turn on your flashlight and put a finger right next to the light source.

You likely won’t feel any heat at all.

If you do feel something, it’s minor.

If you feel a lot of heat, the phone is malfunctioning.

Technically speaking, the LEDs do contribute heat to the phone, but they are a minor player.

Even if your phone was frequently overheating, turning off the flashlight wouldn’t make a difference. 

Something else is the primary heat contributor.

Your flashlight is meaningless in comparison.

Why Would You Leave Your Phone Flashlight On?

Male hand holds a smartphone with a burning flashlight

While you’re wondering if it’s ok to leave the flashlight on, there’s a deeper question that has to be asked.

Why do you want to leave it on in the first place?

There’s an obvious answer.

You have things you need to see. 

If you’re in a setting where light is scarce, and you have stuff to do, you might want to turn on that light and use it for a few hours.

That’s reasonable, and what you can see from the information above is that it’s fine.

The flashlight on the phone is so efficient and safe to use that you could leave it on for no reason and still largely be fine.

But, there’s a general aversion to waste in society, and that can apply to the flashlight as well.

If you don’t have a reason to leave it on, turn it off and enjoy those small battery life savings.

Why Should You Turn Your Phone Flashlight Off?

Beautiful woman looking smartphone at night on the street

Since the flashlight doesn’t hurt the phone, do you ever need to turn it off?

Aside from a general desire to avoid being wasteful, there are a few things to think about. 

Each of them is a reason to turn off the phone, but none of them are overwhelming.

If you need to see, use your phone’s flashlight.

But, if you don’t really need the flashlight, these are reasons that you will want to pay at least a little attention to it.

First, the light is bright.

Especially in a dark setting, it can be bright enough to keep someone awake.

It can make you squint if your eyes are adjusted for night vision. 

The bright light can inadvertently signal people, and it can just plain be annoying.

For all of these reasons, you should probably default to leaving your flashlight off.

There’s also that issue of battery life.

It seems silly to put undue wear on your battery, even if it’s a very small amount of wear.

Batteries are usually the first thing to go as the phone ages, so why should you hasten that if you don’t have to? 

Feel comfortable using the flashlight whenever you really do need the light, but by playing into your innate desire to conserve things, you get just a little more life out of your battery before it goes for good.


  • Theresa McDonough

    Tech entrepreneur and founder of Tech Medic, who has become a prominent advocate for the Right to Repair movement. She has testified before the US Federal Trade Commission and been featured on CBS Sunday Morning, helping influence change within the tech industry.

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