What does SOS stand for?

It isn't short for anything. • • • ▬ ▬ ▬ • • • was chosen because it's easy to send and hard to mistake.

Is there Morse code for other alphabets?

Many alphabets have their own Morse codes. This quiz sticks to the international Latin alphabet.

Do I get the same questions every time?

Every round is generated fresh. Only a friend's challenge link gives you the same questions in the same order.

📡 Morse Code Decoder

Short, long. Which letter is • ▬?

Morse code sends letters using only short signals (•) and long ones (▬). It starts with short letters like E, T and A, then the whole alphabet, then short words like SOS. Miss one and you'll see how it differs from its look-alike.

About this quiz

Morse code was created in the 1830s to send letters over the telegraph. All it needs is short and long signals, so it works with light, sound or tapping, and it's still used for distress signals today.

The first four are short letters like E, T, A and N, the next four can be any letter, and the last two are short words like SOS.

Questions: 10
Subject: Coding
Price: Free
Sign-in: Optional
Devices: Phone, tablet, desktop

How to play

Watch the mirror pairs: Pairs that are just flipped, like A (• ▬) and N (▬ •) or D (▬ • •) and U (• • ▬), show up as each other's wrong answers.
Common letters are short: E, the most common letter in English, is a single dot, and T is a single dash. The more common a letter, the shorter its code.
Review only what you missed: Under your result you'll find each question you missed, what you picked, the right answer and the working. Finish a round and your review is done too.

Score ranks

Radio Ace
You read every one from dots and dashes alone. You're in charge of secret messages.
Seasoned Operator
Almost all of them. Just watch the mirror pairs, like A and N.
Flashlight Signaller
The short letters are solid. The four-signal ones probably tripped you.
Start With SOS
At first it all looks the same. Learn E (•) and T (▬) and you'll improve fast.

Frequently asked questions

What does SOS stand for?: It isn't short for anything. • • • ▬ ▬ ▬ • • • was chosen because it's easy to send and hard to mistake.
Is there Morse code for other alphabets?: Many alphabets have their own Morse codes. This quiz sticks to the international Latin alphabet.
Do I get the same questions every time?: Every round is generated fresh. Only a friend's challenge link gives you the same questions in the same order.