Nerve Conduction Velocity Calculator
The conduction velocity of a nerve from the latencies at two stimulation sites and the distance between them — the standard nerve conduction study calculation — with a comparison against a normal lower limit.
Stimulate a nerve at two points and record the response at the same muscle: the difference in latency is the time the impulse took to travel between the two points, and the distance divided by that time is the velocity.
How the nerve conduction velocity calculator works
Stimulate a nerve at two points and record the response at the same muscle: the difference in latency is the time the impulse took to travel between the two points, and the distance divided by that time is the velocity. Using two sites cancels the delay at the neuromuscular junction, which is why one latency alone is not enough.
Healthy large myelinated fibres conduct at 50 to 70 metres per second in the arm; a slowing below about 40 suggests demyelination, and the lower limit differs by nerve.
Formula: CV = distance / (proximal latency − distal latency)
Worked examples
| Inputs | Conduction velocity (m/s) | Note |
|---|---|---|
| A normal median nerve | 50 | 50 m/s |
| Slowed | 33.33 | 33 m/s — demyelination |
| A leg nerve | 43.84 | 44 m/s — normal for the leg |
FAQFrequently asked questions
What is nerve conduction velocity?
How fast an electrical impulse travels along a nerve, measured by stimulating at two points and timing the responses. It is the core measurement of a nerve conduction study.
Why two stimulation sites?
Because a single latency includes the delay at the nerve–muscle junction and in the muscle itself. Subtracting two latencies leaves only the travel time along the nerve.
What is normal?
Roughly 50 to 70 m/s in arm nerves and 40 to 60 in leg nerves, slower in the cold and in the elderly. Each laboratory has its own limits, which is why the lower limit is an input.
What does slowing mean?
Marked slowing points at the myelin sheath — demyelinating conditions. Loss of axons reduces the response size more than its speed.
Does temperature matter?
About 2 m/s per degree — a cold limb reads slow. Studies warm the limb to a standard temperature before measuring.
Where these figures come from
- NCBI Bookshelf — Molecular Biology of the Cell — growth kinetics and molecular conventions
- CSIRO — Australia's national science agency
Last checked: September 2026. Formulas are the standard textbook forms; assumptions are stated on each page because they are where these models break.