Variometer
![The vertical speed indicator from a Robinson R22. This is the most common type used in aircraft, showing speed in feet per minute](/Images/godic/202501/21/R22-VSI5348.jpg")
![A variometer for paragliders, hang gliders, and ballooneers, showing vertical speed with both a ribbon indicator and a numeric readout](/Images/godic/202501/21/Gleitschirmvario5348.jpg")
![Schematic drawing of the internals of a classic aircraft vertical speed indicator](/Images/godic/202501/21/Faa_vertical_air_speed5348.JPG")
![Panel mounted variometer for gliders](/Images/godic/202501/21/Cair-Xk10-vario5348.jpeg")
A variometer (also known as a rate of climb and descent Indicator (RCDI), rate-of-climb indicator, vertical speed indicator (VSI), or vertical velocity indicator (VVI)) is one of the flight instruments in an aircraft used to inform the pilot of the near instantaneous (rather than averaged) rate of descent or climb. It can be calibrated in feet per minute, knots (1 kn ≈ 100 ft/min) or metres per second (1 m/s ≈ 200 ft/min), depending on country and type of aircraft.