Online Morse trainer

1. 1

   Pick the characters: Course characters, Letters A–Z, Numbers 0–9, Letters and digits, or Your own set.

2. 2

   Leave Slow ones more often on, so the characters you answer slowest come up more.

3. 3

   Set the speed: 20 WPM or faster keeps characters too quick to count.

4. 4

   Press Start. When you hear a character, press its key, or tap it on the answer keys.

5. 5

   After 20 characters, read your average and what to work on, then your time per character below.

6. 6

   As you get quicker, set a time limit of 3, 2 or 1.5 seconds.

• Times every answer. The clock starts when the character ends, so a long 0 is not slower than E by design. A right answer in 1.5 seconds or less counts as instant; one pressed before the character ends is not timed.

• Your time per character. Under the trainer, every character in play with its median time from your last right answers and how often you get it right, slowest first.

• Slow ones more often. Each round picks the characters you answer slowest or miss more often, until they catch up.

• Your characters. Course characters follow the Koch method course; or take letters, numbers, letters and digits, or type your own set of problem characters.

• Works on a phone. On-screen answer keys show only the characters in play.

• Feeds the review. Every answer goes into the daily review; quick right answers move a character up faster.

The trainer plays one character at your speed and starts the clock when the sound ends; the time to your key press or tap is your time for that character.

Timing follows ITU-R M.1677-1: a dot is one unit, a dash three, and one unit separates the parts of a character. A unit lasts 1,200 ÷ WPM milliseconds, counted on the word PARIS, so the length of each character depends on the speed (the table under Examples).

Instant recognition means knowing the character as a sound, without counting its dots and dashes. The trainer marks a right answer in 1.5 seconds or less as instant; the morsecode.world ICR trainer sets a stricter 600 ms, which includes saying the letter aloud.

Each character keeps the times of its last 30 right answers on your device. An answer pressed before the character has finished counts as right or wrong but has no time, so a guess never counts as instant. Your time per character is their median, so one slow answer does not spoil it.

With Slow ones more often on, each round of 20 is drawn with a weight for every character: its median time in seconds (3 seconds if it has none yet, never under 0.25), times 1 + 2 × its share of misses in the last 30 tries. A character twice as slow comes up twice as often.

How long a character lasts at each speed (from its first element to its last):