Screen Flash Tester
Preview what screen-flash notifications look like. Click anywhere or press Esc to stop.
Photosensitivity warning: flashing light can trigger seizures in people with photosensitive epilepsy. Skip this tool if that applies to you.
Why test screen flash before enabling it?
Phones can blink the screen or the camera LED when calls and messages arrive — an accessibility feature for deaf and hard-of-hearing users, and genuinely useful for anyone in loud workshops, concerts, or silent meetings. But flash alerts are a very personal setting: a speed that feels attention-grabbing to one person feels alarming to another. This tool lets you preview blink speeds and colours before you commit to changing your phone’s settings.
How to use the tester
- Pick a blink speed — 500 ms is a comfortable default; faster values feel more urgent.
- Choose a colour — white matches most phones’ behaviour; softer colours are gentler at night.
- Press Start Flashing. The whole screen blinks so you can judge visibility from across a room.
- Click anywhere or press Esc to stop.
Recommended settings by use case
| Use case | Suggested speed | Notes |
|---|---|---|
| Accessibility (primary alert method) | 400–600 ms | Fast enough to catch attention reliably |
| Loud environment backup | 500–800 ms | Pair with vibration |
| Night-time / bedside | 1000+ ms, warm colour | Less jarring when waking |
How to enable flash alerts on your phone
iPhone: Settings → Accessibility → Audio/Visual → LED Flash for Alerts. Optionally enable “Flash on Silent” so it only blinks when the ringer is off.
Samsung: Settings → Accessibility → Advanced settings → Flash notification → choose Camera flash, Screen flash, or both.
Other Android: Settings → Accessibility → Hearing enhancements (naming varies by brand) → Flash notification.
Screen flash vs camera (LED) flash
Screen flash lights the entire display, works face-up or face-down in either orientation, and uses less battery. Camera LED flash is brighter and visible from farther away, but is missed if the phone lies face-up and drains more power. Many users enable both for a week, then keep whichever they actually notice.
Important: photosensitivity warning
Flashing light can trigger seizures in people with photosensitive epilepsy. If you or anyone near your screen has photosensitive epilepsy, do not use this tool, and prefer vibration-based alerts on your phone. Slower blink speeds (above 1000 ms) and lower screen brightness reduce — but do not eliminate — the risk.
Frequently asked questions
Does this tool change my phone’s settings?
No. It only previews the effect inside your browser. Your phone’s actual flash alert settings are changed in the Settings app, using the paths above.
Why doesn’t the test use my camera LED?
This page tests screen flash. To test your camera LED and its permission, use our Flashlight Test tool.
Will flash alerts drain my battery?
Screen flash has a minor impact. Camera LED flash uses noticeably more power if you receive many notifications — if battery matters, choose screen flash.
Can I get flash alerts for specific apps only?
On Samsung and recent Android versions, yes — flash notification settings let you exclude apps. On iPhone, LED Flash for Alerts applies to all notifications.