Morse Code Light
Type a message and this tool flashes it in Morse code on your screen or, on Android phones, with the camera flashlight. A dot is a short flash and a dash is a flash three times longer.
Warning: this tool flashes light. Do not use the screen flash if you are sensitive to flashing lights.
Phone flashlight works in Chrome on Android. On iPhone, use Full screen with brightness turned up.
How a Morse Code Light Signal Works
Light uses the same timing as sound. Everything is measured in units, where one unit is the length of a dot. The gaps matter as much as the flashes: without them, a reader cannot tell where one letter ends. More detail is in the Morse code timing guide.
| Element | Light state | Length | At 10 WPM | At 15 WPM |
|---|---|---|---|---|
| Dot | On | 1 unit | 120 ms | 80 ms |
| Dash | On | 3 units | 360 ms | 240 ms |
| Gap inside a letter | Off | 1 unit | 120 ms | 80 ms |
| Gap between letters | Off | 3 units | 360 ms | 240 ms |
| Gap between words | Off | 7 units | 840 ms | 560 ms |
Light is harder to read than sound, so start slower than you would with audio. Around 10 words per minute is comfortable for most people watching a flashlight.
Messages People Flash Most
SOS is the one signal worth memorizing. By light it is sent as nine flashes with no letter gaps: three short, three long, three short. Type it in the box above to see the rhythm.
Screen Flash vs Phone Flashlight
Android phones
Chrome on Android lets a web page control the rear flashlight. Tap Phone flashlight, allow camera access once, and the LED flashes your message.
iPhone and iPad
Apple does not let websites control the flashlight. Use Full screen, turn brightness to maximum, and point the screen toward the person reading.
Laptops and desktops
The screen flash works in any modern browser. Full screen mode makes the light larger and easier to see across a room.
A real torch
For distance, a torch with a push button is easier to time than a phone. Practice the rhythm here first, then send it by hand.
Morse Code by Light in the Real World
Ship signal lamps
Ships have long used shuttered signal lamps, often called Aldis lamps, to flash Morse between vessels. Read more in Morse code at sea.
Navigation buoys
Some buoys and lights flash a Morse letter as their pattern. A safe water mark, for example, can show the letter A (short-long), written Mo(A) on nautical charts.
Blinking a message
In 1966, US Navy pilot Jeremiah Denton, then a prisoner of war, blinked T-O-R-T-U-R-E in Morse during a filmed interview. See how to blink or tap Morse code.
Survival signaling
A flashlight can send SOS at night when a voice will not carry. Learn the pattern on the SOS in Morse code page before you need it.
Frequently Asked Questions
How do you do Morse code with a flashlight?
Turn the light on briefly for a dot and about three times longer for a dash. Leave the light off for one dot-length between signals, three between letters and seven between words. The tool above times this for you.
How do you say SOS with a flashlight?
Flash three short, three long, three short: ... --- .... Send it as one continuous group without letter gaps, pause, and repeat until you get a response.
Can my phone flashlight flash Morse code from a website?
On Android, Chrome lets a web page switch the camera flashlight on and off, so the Phone flashlight button works after you allow camera access. iPhone browsers do not allow this, so use the full-screen screen flash instead.
What speed should I use for a Morse code light?
Light is harder to read than sound, so 8 to 12 words per minute is a good range. At 10 WPM a dot lasts 120 milliseconds and a dash 360 milliseconds, which most people can follow by eye.
Can flashing lights be dangerous?
Flashing lights can trigger seizures in people with photosensitive epilepsy. If you or anyone watching is sensitive to flashing light, do not use the screen flash.
What is a Morse code signal lamp called?
A handheld signal lamp with a shutter is often called an Aldis lamp. Ships used them to send Morse code by light, and navies still train sailors to use signal lamps when radio silence is required.