Climb Gradient Calculator
Convert a climb gradient to the rate of climb you need at your ground speed.
Inputs
Result
Required rate of climb
584fpm
At 100 kt ground speed
Climb gradient
350ft/nm
Gradient (percent)
3.3° climb path
5.8%
350 ft/nm (5.8%) needs 584 fpm at 100 kt
Formula
Ref- Gradient (ft/nm) = tan(angle) × 6076
- Gradient (%) = ft/nm ÷ 6076 × 100
- Rate of climb (fpm) = ft/nm × ground speed ÷ 60
Worked example
RefRequired 3.3° climb path at 100 kt ground speed.
- 1.Gradient = tan(3.3°) × 6076 ≈ 350 ft/nm.
- 2.= 350 ÷ 6076 × 100 ≈ 5.8%.
- 3.ROC = 350 × 100 ÷ 60 ≈ 583 fpm.
≈ 350 ft/nm (5.8%) needs ≈ 583 fpm at 100 kt.
How it works
RefDeparture procedures publish a minimum climb gradient in ft/nm or percent; what you fly is a rate of climb in fpm, which depends on your ground speed. This converts the required gradient into the rate you must achieve — the faster the ground speed, the higher the fpm needed for the same gradient.
DGCA student tip
ExamRemember gradient is distance-based but rate is time-based, so a tailwind (higher GS) demands a HIGHER rate of climb to hold the same gradient. A 3.3% gradient is roughly 200 ft/nm; the standard PANS-OPS minimum is 3.3%.
Common mistakes
Watch- Confusing ft/nm (gradient) with fpm (rate) — they aren't interchangeable.
- Assuming a tailwind helps the climb gradient; it needs a higher rate.
- Mixing percent and degrees for the path angle.