Climb Gradient Calculator

Convert rate of climb to climb gradient (ft/NM and %), check against departure procedure requirements, and verify obstacle clearance.

Rate of Climb

fpm

C172 sea level: ~730 fpm, at 5000 ft: ~530 fpm

Ground Speed

Vy climb: 70–90 kt for light aircraft

Required Gradient

ft/NM

Tab to move between fields

Climb Gradient

375 ft/NM

Meets Requirement?

Yes

Climb Gradient6.2%

ROC Needed for Requirement267 fpm

How to Use This Calculator

How the result changes with Ground Speed

Rate of Climb: Your aircraft's rate of climb from the POH at current weight, altitude, and temperature.
Ground Speed: Ground speed during the climb (typically Vy climb speed adjusted for wind).
Required Gradient: Minimum gradient from the departure procedure (ODP or SID). Standard is 200 ft/NM unless noted otherwise.
Obstacle Height (AGL): Height of obstacle to clear above departure end of runway.
Obstacle Distance: Distance from departure end of runway to obstacle.

ROC Needed for Requirement: Minimum rate of climb to meet the required gradient at your ground speed.

Climb Gradient (ft/NM)
Gradient = (Rate of Climb ÷ Ground Speed) × 60
(500 fpm ÷ 80 kt) × 60 = 375 ft/NM
Climb Gradient (%)
% = (ft/NM ÷ 6076.12) × 100
(375 ÷ 6076) × 100 = 6.2%
ROC Needed for Required Gradient
ROC = (Required Gradient × GS) ÷ 60
(200 × 80) ÷ 60 = 267 fpm