Morse code timing calculator

Morse code is defined by a single time unit — call it u. Every element of the system is a multiple of u, so changing the speed means changing one number and the rest scales:

• Dit (·) — 1 u
• Dah (−) — 3 u
• Intra-character gap (between dits/dahs in one letter) — 1 u
• Inter-letter gap — 3 u
• Inter-word gap — 7 u

The PARIS standard fixes the WPM ↔ unit conversion: the word PARIS plus a trailing inter-word gap is exactly 50 units. So at W words per minute:

unit_ms = 60_000 ms / minute
        ÷ (W words/minute × 50 units/word)
       = 1200 / W

At 20 WPM that's 60 ms per unit. A dit is 60 ms, a dah is 180 ms, the gap between "DO" and "G" is 180 ms, and the gap between "DOG" and "CAT" is 420 ms.

Farnsworth timing

Beginners often plateau when they try to learn at 5 WPM because the slow rhythm encourages dot-counting. Farnsworth timing keeps each character at the target speed (so the rhythm sounds right from day one) but stretches the inter-letter and inter-word gaps so the overall effective WPM is slower.

At 20 WPM character speed with 12 WPM effective speed, characters still play at 60 ms per unit, but the gaps between letters and words are widened by a multiplier of roughly (c − f) / f where c is character WPM and f is effective WPM. The calculator above shows you the exact multiplier.

Common speed targets

• 5 WPM — old FCC entry licence; almost no one targets this anymore.
• 12–15 WPM — comfortable copying speed for amateur QSOs.
• 18–20 WPM — the modern "fluent" benchmark; most contesters live here.
• 25–30 WPM — fast contest CW.
• 40+ WPM — head-copy territory; rare outside high-speed contests.