Rate of Climb (ROC)
Embed This Widget
Add the script tag and a data attribute to embed this widget.
Embed via iframe for maximum compatibility.
<iframe src="https://planefyi.com/iframe/glossary/rate-of-climb/" width="420" height="400" frameborder="0" style="border:0;border-radius:10px;max-width:100%" loading="lazy"></iframe>Paste this URL in WordPress, Medium, or any oEmbed-compatible platform.
https://planefyi.com/glossary/rate-of-climb/Add a dynamic SVG badge to your README or docs.
[](https://planefyi.com/glossary/rate-of-climb/)Use the native HTML custom element.
Definition
The vertical speed at which an aircraft gains altitude, measured in feet per minute.
What Is Rate of Climb (ROC)?
Rate of Climb (ROC) is the vertical component of an aircraft's velocity — the speed at which it gains altitude — expressed in feet per minute (ft/min) or meters per second. It is a critical performance parameter governing how quickly an aircraft can reach its cruise altitude, clear obstacles after departure, and respond to ATC climb clearances. ROC depends on the excess thrust available above what is required to maintain level flight: a higher power-to-weight ratio produces a greater rate of climb. ROC decreases as altitude increases (air density falls, reducing engine thrust and aerodynamic efficiency), which is why the service ceiling is defined at the altitude where ROC has degraded to 100 ft/min.
How It Is Measured
ROC is measured using the vertical speed indicator (VSI) in the cockpit, which senses the rate of change of static pressure and converts it to a vertical speed readout. For performance calculations, ROC is computed from the specific excess power (Ps) formula: ROC = (Thrust − Drag) × TAS / Weight. Maximum ROC occurs at the speed that maximizes excess thrust, called Vy (best rate-of-climb speed) for piston aircraft and a similar optimum speed for jets. During initial climb, jet transports typically climb at reduced speed to limit noise exposure near airports while still maintaining FAA-required obstacle clearance climb gradients (typically 2.4% for one-engine-inoperative conditions). V-speeds define these critical climb performance benchmarks.
Typical Values by Aircraft
| Aircraft | Initial ROC (ft/min) | Cruise Climb (ft/min) | Time to FL350 |
|---|---|---|---|
| Airbus A320neo | ~2,500 | ~1,200 | ~22 min |
| Boeing 737 MAX 8 | ~2,500 | ~1,200 | ~22 min |
| Boeing 787-9 | ~2,900 | ~1,400 | ~20 min |
| Airbus A350-900 | ~3,100 | ~1,500 | ~18 min |
| F-15 Eagle | 50,000+ | N/A | <2 min |
| Cessna 172S | 730 | ~400 | ~45 min (FL120) |
Military aircraft with thrust-to-weight ratios exceeding 1.0 can climb vertically. Transport aircraft achieve peak ROC in the range of 2,500–3,500 ft/min at sea level, declining to 500–1,000 ft/min near the service ceiling.
Why It Matters
ROC determines how quickly an aircraft reaches its efficient cruise altitude, directly affecting fuel consumption on short-to-medium routes where climb represents a significant portion of total flight time. A higher ROC reduces time spent in the fuel-intensive low-altitude climb environment and shortens the overall departure sequence, improving on-time performance and reducing noise impact near airports. For airlines, thrust rating selection and derate strategies during climb balance ROC against engine wear and maintenance costs — higher thrust accelerates wear, so many operators use reduced thrust climb profiles whenever obstacle clearance allows.