Climb gradient and vertical speed
Converts a climb or descent gradient (feet per nautical mile, percent, or degrees) to the vertical speed you need at a groundspeed, or the reverse.
Planning and education aid. Not for primary navigation. Full disclaimer
Experimental: not yet fully verified. How results are checked
At that groundspeed, 200 ft/NM takes 400 ft/min.
- Gradient
- Gradient
- Angle
Provenance
- Computed by
- aviation.performance.climb-gradient 1.0.0, core 0.1.0
- Model
- Vertical speed = groundspeed × gradient (rise over horizontal run); 1 ft/NM = 0.3048/1852
- Accuracy
- Exact. Planning aid, not certified for navigation.
- Notes
- 1 shown with the answer
- Cites
- Federal Aviation Administration, Instrument Procedures Handbook, FAA-H-8083-16B
Something look off?
How we got thisFormula, worked example, sources, and proof
Model: Vertical speed = groundspeed × gradient (rise over horizontal run); 1 ft/NM = 0.3048/1852
Accuracy: Exact. Planning aid, not certified for navigation.
Worked example: 200 ft/NM at 120 kt. Source: add-aviation-suite climb scenario: 400 fpm. It is golden test vector v001, and every build checks the tool still gives its answer within its tolerance.
You enter
- Gradient
- 200 ft/NM
- Groundspeed
- 120 kt
You get
- Vertical speed
- 400 ft/min
- Gradient
- 200 ft/NM
- Gradient
- 3.29%
- Angle
- 1.89°
Review: Not yet independently reviewed by a flight instructor (CFI).
Last verified: 2026-09-18, when a maintainer last confirmed this tool's sources at the issuer. See the sources ledger.
Status: version 1.0.0, core 0.1.0. See this tool in the verification report.
Checked against: 5 golden test vectors (download the test vectors, each with its source and tolerance). See how results are checked and every source.
Sources
- Instrument Procedures Handbook, FAA-H-8083-16B, Federal Aviation Administration, FAA-H-8083-16B. Chapter 2 (descent planning) and Chapter 4 (visual descent point, vertical descent angle).
Experimental means this tool has not yet met the stable bar: at least 20 golden vectors, differential tests, and an independent worked example.