Calculate descent gradient in feet per nautical mile and percent using rate of descent and groundspeed. This free aviation calculator helps pilots with descent planning, approach awareness, and training.
Enter rate of descent and groundspeed to estimate descent gradient in feet per nautical mile and percent.
This calculator estimates average descent gradient over the ground using rate of descent and groundspeed.
Descent gradient describes how much altitude an aircraft loses compared with the horizontal distance it travels. It is commonly expressed in feet per nautical mile or as a percent.
Unlike rate of descent, which is vertical speed in feet per minute, descent gradient shows how steep the descent is over the ground. This makes it useful for approach planning and path awareness.
| Descent Gradient | Meaning |
|---|---|
| 318 ft/NM | Approximate 3° descent path |
| 400 ft/NM | Steeper descent path |
| 500+ ft/NM | Very steep descent path |
No. Rate of descent is vertical speed in feet per minute. Descent gradient compares altitude lost to horizontal distance traveled.
A higher groundspeed means the aircraft travels farther over the ground each minute. Even with the same rate of descent, the descent gradient becomes shallower as groundspeed increases.
It is the approximate descent gradient for a standard 3 degree descent path.
Yes, as a planning aid. Pilots should always use approved procedures, aircraft data, and current operational guidance for actual flight decisions.