Calculate pivotal altitude from ground speed, or find ground speed from altitude, with optional pylon elevation and wind-based MSL results.

Result is height above the ground reference. Enter its elevation for an MSL estimate.

FAA rule-of-thumb estimate using groundspeed, not indicated airspeed. Wind changes the height throughout a turn. Use flight instruction and the actual pylon sight line for the maneuver.

Optional settings

Blank omits MSL altitude; negative elevations are allowed.

Pivotal Altitude Formula

The following two example problems outline the steps and information needed to calculate the Pivotal Altitude.

PA = GS² / 15

Variables:

  • PA is the approximate height above the ground reference (ft)
  • GS is the ground speed (MPH) 

Using the FAA rule of thumb, square groundspeed in mph and divide by 15 for feet above the ground reference. Add the reference’s MSL elevation for estimated MSL altitude. Use groundspeed rather than indicated airspeed; wind changes pivotal altitude during a turn.

How to Calculate Pivotal Altitude?

The following steps outline how to calculate the Pivotal Altitude.

  1. First, determine the ground speed (MPH). 
  2. Next, gather the formula from above: PA = GS^2 / 15.
  3. Finally, calculate the Pivotal Altitude.
  4. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

ground speed (MPH) = 150

PA ≈ 150² / 15 = 1,500 ft above the ground reference.