How to Send Morse Code With a Flashlight: Dots, Dashes & Timing

To send Morse code with a flashlight, flash the light briefly for a dot and three times as long for a dash. Keep it dark for one unit between flashes in the same letter, three units between letters and seven units between words. For a first attempt, make one unit about half a second, so a dot is half a second of light and a dash is a second and a half.

The rest of this page turns those rules into something you can do with a real torch: how to time it by hand, whether to use the switch or cover the lens, where to point it, and short messages to practise.

The method in six steps

1. Write the message down in Morse first. Use our Morse Code Translator and keep the result in front of you.
2. Pick a unit and stick to it. Between a quarter and half a second is realistic for a beginner.
3. Dot: light on for one unit. A crisp, short flash.
4. Dash: light on for three units. Count “one-two-three” in your head.
5. Dark gaps: one unit inside a letter, three between letters, seven between words.
6. Repeat the whole message after a long dark pause, so the watcher can check what they saw.

For example, --- -.- is three long flashes, a three-unit dark gap, then long, short, long.

Short flash and long flash

Everything in International Morse code is measured against the dot. The ITU’s Recommendation ITU-R M.1677-1 sets a dash equal to three dots, and the same 1 to 3 ratio applies to light.

• Short flash (dot): one unit of light. It should look like a blink of the beam, not a flicker.
• Long flash (dash): three units of light. It should look clearly held, not just “a bit longer”.

Light has one extra quirk. The International Code of Signals, which ships use for visual signalling, advises that in flashing light it is best to “err on the side of making the dots rather shorter in their proportion to the dashes”, because that makes the two elements easier to tell apart (Pub. 102, International Code of Signals, Chapter 1). In practice, if your dots and dashes look similar to the watcher, shorten the dots rather than stretching the dashes.

Timing for a flashlight

Morse speed is usually given in words per minute (wpm), and one unit in milliseconds is 1,200 divided by the wpm. At 20 wpm a dot lasts 60 milliseconds, which is far too quick for a hand on a switch and for most people watching a torch. The general rules are on our homepage in the timing and spacing section; here they are at flashlight pace.

Start at half a second. Once your flashes are even, move towards a quarter of a second. The ratios never change: every row keeps the dash at three units, the letter gap at three units and the word gap at seven.

For comparison, the International Code of Signals says the standard rate for flashing light is “forty letters per minute”. If you count five letters as a word, that is roughly 8 wpm, with a unit of about 150 milliseconds. That is the pace of a trained signaller with a proper signal lamp, so do not expect to match it at first.

How long real messages take

Because every message has a fixed number of units, you can predict how long it will take to send. These totals include the gaps inside the message but not a pause afterwards.

This is why flashlight messages should be short. A ten-word sentence at beginner pace can take a few minutes, and the watcher has to stay focused for all of it.

Letter gaps and word gaps in the dark

The dark periods carry as much information as the flashes. A watcher decides where one letter ends and the next begins purely from how long the light stays off.

• Inside a letter (1 unit): the light is off for about as long as a dot. The flashes of one letter should feel like a single group.
• Between letters (3 units): off for as long as a dash. Long enough to notice, short enough to keep the word together.
• Between words (7 units): off for more than twice a letter gap. The watcher should sense a clear break.

If the gaps shrink, letters merge into other letters. . - flashed without its letter gap is read as .-, and .. - without its gap becomes ..-. Beginners often make gaps too short, because dark time feels like wasted time.

A simple habit fixes most of this: count the dark as well as the light. “One” in the dark inside a letter, “one-two-three” between letters, and a full count to seven between words.

The demonstration below flashes a short message slowly and narrates every element and gap with its length in units and milliseconds. Watch it once with the sound off, then hold your own torch and copy it. Choose 4 wpm for the slowest pace.

Switch the light or cover the lens?

There are three common ways to make the flashes, and the right one depends on your light.

Some flashlights have a clicky switch that cycles through brightness or strobe modes each time it is pressed. If yours does, a full click can change the mode instead of turning it off. Look for a half-press or momentary-on action, or cover the lens instead.

Covering the lens is the same idea used by real signal lamps. According to the Wikipedia article on signal lamps, large lamps open and close shutters in front of the light, while handheld lamps tilt a mirror with a trigger, so the lamp itself stays lit. An older incandescent bulb can also glow for a moment after switching off, which blurs short flashes; most LED lights switch almost instantly.

For covering by hand, use a flat piece of card or the palm of your hand held close to the lens, and move it in one quick, straight motion. A card gives a sharper edge than fingers.

Positioning and aim

A perfectly timed message is useless if the watcher cannot see it clearly. Before you send, check these points.

1. Line of sight. The watcher must see the lens or the beam directly, with nothing in between. Branches, glass reflections and people walking past all interrupt it.
2. Aim at the watcher, not into their eyes at close range. At a distance, point the beam towards them. In a room, bounce it off a wall or ceiling they can see instead of shining it in their face.
3. Hold the light steady. Brace your elbow against your body, a railing or a table. A wobbling beam flickers on its own and looks like extra dots.
4. Keep the same angle. If you tilt the torch between flashes, the brightness changes and dots can seem to disappear.
5. Mind the background. A dark background behind you makes flashes stand out. Street lights, car headlights or a lit window behind you compete with your signal.
6. Send a test. Flash one easy letter, such as -.-, and ask the watcher to confirm before the real message.

Never aim a bright torch at drivers, aircraft or boat crews. Even a brief dazzle can be dangerous.

Visibility: what helps and what hurts

How far a flashlight signal can be read depends on too many things to give a single distance: the brightness of the light, how dark it is, the air, the angle, and the watcher’s eyesight. Test with your own light and your own watcher before relying on it.

Two habits help most at a distance. Slow down, because short flashes are harder to catch as a light gets fainter. And start with a few seconds of steady light or a repeated test letter so the watcher knows exactly where to look.

Blinking Morse code without a flashlight

The same timing works with any light you can switch or cover: a lamp, a bike light, a phone screen, or a room light switch. It even works with your eyes, a quick blink for a dot and a held blink for a dash, though eye blinks are hard to time and easy to miss unless the watcher is close and paying attention.

Physical tapping follows the same 1:3 and 1:3:7 ratios, with its own problem that a knock has no length. Our guide on how to tap Morse code covers that method.

Practise with the flashlight button

Before you pick up a torch, rehearse the press lengths here. Hold the button with a mouse, a finger or the Space bar as if it were your flashlight’s momentary switch. It measures each press against the speed you choose, shows the length in units, and decodes your flashes back into letters.

At 5 wpm one unit is 240 milliseconds, close to the quarter-second flashlight pace. A press shorter than two units is read as a dot and anything longer as a dash, and the pad waits three units of silence before closing a letter. If your letters split or merge, adjust your timing here first, then move to the real light.

A practice sequence

Work through these stages with a partner watching, or film yourself on a phone and play it back.

1. Single dots and dashes. Flash . and - ten times each, one letter gap apart. Every dot the same, every dash the same.
2. Pure letters. ... (three short) and --- (three long). Keep the dark inside the letter at one unit.
3. Mixed letters. .-, -., -.-, .-.. Watch that the switch from short to long does not change the gap.
4. Gap check. Flash E, then T, with a proper three-unit gap. Your watcher should read E T, not A. Then do I and T, which must not become U.
5. Words. Move on to the short messages below.
6. Receive as well as send. Swap roles. Reading someone else’s flashes quickly shows why the gaps matter.

For listening drills that build the same recognition by ear, see our Morse code practice guide.

Short messages to send

Short, useful words make the best flashlight practice. Send each one twice with a long dark pause between repeats.

SOS is included as a rhythm pattern. The International Code of Signals reproduces the collision regulations’ list of distress signals, which includes SOS made “by radiotelegraphy or by any other signaling method”, but no hand-flashed signal is guaranteed to be seen or understood, so it should never be the only way you try to get help.

If you want to flash a personal message, our guide to I love you in Morse code works through that phrase flash by flash.

How ships signal with light

Flashing Morse has a long practical history at sea. Ships have long used signal lamps, often called Aldis lamps, and navies still use them, for example when radio silence is needed. The International Code of Signals sets out a procedure for flashing light: a call, an exchange of identities, the text with each word acknowledged by the receiver flashing -, and an ending signal, AR, sent as one run-together group (.-.-.) and answered with .-. for “received”.

You do not need the full procedure for casual signalling, but two ideas from it are worth borrowing. Have the watcher flash back a short acknowledgement after each word, so you know when to continue. And agree on a clear end signal, so neither of you waits for more.

Common mistakes

• Dashes that are only slightly longer than dots. At a distance, a flash of two units looks like a dot. Hold dashes for a full three units, and keep dots short.
• Gaps that are too short. A common cause of misread letters. E and T become A; I and T become U.
• A shaky beam. A beam that wobbles away from the watcher looks like extra flashes. Brace your arm.
• Clicking through modes. On lights with mode-cycling switches, a full click may change brightness or start a strobe. Use a momentary press or cover the lens.
• Speeding up. It is easy to start slowly and rush the end. Keep the same unit from the first flash to the last.
• Sending once. One pass is easy to miss, especially the first letter while the watcher is still finding your light. Repeat the message.
• Starting without warning. Show a steady light or a test letter first so the watcher is ready.

Watch the translator flash it for you

If you want to see what correct timing looks like before you try it by hand, type your message into our translator and turn on Light playback. The on-screen beacon flashes the message on the same schedule as the audio, at any speed from 5 to 40 wpm. Set it slow, watch a word a few times, then copy the rhythm with your own flashlight.