CW Words Per Minute Calculator

The CW Words Per Minute Calculator derives every Morse code timing value from a single input: your operating speed in words per minute. It outputs dit and dah durations in milliseconds, inter-element gaps, inter-character gaps, inter-word gaps, Farnsworth spacing parameters, and an estimated transmission time for any message length. CW (continuous wave) Morse telegraphy remains one of the most signal-efficient modes in amateur radio, capable of being copied by a trained ear at signal levels that render SSB voice completely unintelligible.

Morse code timing in amateur radio follows the PARIS standard, named after the test word "PARIS." One occurrence of "PARIS" contains exactly 50 dit-lengths when all characters and spaces are counted using standard element weights. That means 1 WPM is defined as sending PARIS once per minute, yielding a dit duration of exactly 1200 / WPM milliseconds. At 20 WPM — a typical on-air operating speed — the dit is 60 ms and the dah is 180 ms. This simple relationship governs every timing value derived by this calculator.

Farnsworth spacing is a training technique developed to help beginners learn CW more efficiently. Characters are sent at a higher speed (e.g., 20 WPM) so the student hears them as distinct sound patterns rather than countable individual dits and dahs, while the inter-character and inter-word gaps are artificially stretched to bring the overall message speed down to a learnable pace (e.g., 10 WPM effective). As the student improves, the gap stretch is reduced until character speed and overall speed match. Most software trainers including the G4FON Koch CW Trainer and LCWO support Farnsworth mode natively.

For on-air use, knowing your exact timing helps calibrate electronic keyers and verify that paddle pressure settings produce the correct dit-to-dah ratio. Contest operators running CW at 30–35 WPM benefit from understanding how transmission time per exchange scales with speed, which directly affects how many QSOs per hour are theoretically achievable at a given rate. At 30 WPM, a typical contest exchange of 20 characters takes approximately 5–6 seconds to send.

The single most common mistake in CW training is increasing speed before achieving reliable copy at the current speed. The Koch method specifies adding a new character only when you can copy the existing set at 90% accuracy or better, typically starting at 20 WPM characters with Farnsworth spacing. Trying to copy at 5 WPM and then jumping to 15 WPM creates a gap where the brain counts individual elements instead of hearing words as patterns — the so-called "code plateau." Using this calculator to track your actual dit duration helps you understand exactly what your ears need to process as you increase speed.

On-air CW operating runs faster than most beginners expect. A casual HF ragchew runs 13–18 WPM; DX contacts run 20–25 WPM; competitive contesting runs 28–35+ WPM. When calling CQ on 40m CW, send your callsign at your comfortable copy speed — not your maximum sending speed. Other operators will reply at the speed you use, so sending at 25 WPM when you can only copy 15 WPM will produce frustrating exchanges. Matching send and receive speed is a basic on-air courtesy.

For QRP portable operation (POTA, SOTA, field day), knowing your transmission time helps manage battery consumption. At 15 WPM with a 5-watt transceiver drawing 1.5 A on transmit and 0.3 A on receive, a typical QSO where you transmit for 30 seconds out of each 90-second cycle burns roughly 0.021 Ah per QSO. Over a 4-hour activation with 60 QSOs at a 1:3 TX:RX duty cycle, you draw approximately 1.3 Ah — well within a 5 Ah LiFePO4 battery budget.