Convert a required climb gradient (ft/nm or %) and ground speed into rate of climb in fpm for departure-procedure compliance.
Planning estimate only — verify against your aircraft's certified climb performance and the published procedure.
About this tool
The Climb Gradient & Rate of Climb Calculator converts a required climb gradient into the rate of climb you must achieve at your ground speed, so you can check compliance with a departure procedure (SID) or an obstacle-clearance requirement. Enter values two ways: from a climb height and distance, or from a gradient given directly in feet per nautical mile. It computes entirely in your browser.
The gradient in feet per nautical mile is climb ÷ distance (or the value you enter). The rate of climb is ground speed × gradient ÷ 60 feet per minute, because ground speed ÷ 60 is nautical miles per minute. The gradient as a percentage is gradient ÷ 60.76, since a 1% slope equals 60.76 ft/nm, and the climb angle is arctan(gradient ÷ 6076.12).
Many SIDs publish a minimum climb gradient such as 200 or 350 ft/nm until a given altitude. Enter that value, set your expected ground speed, and confirm the required fpm is within your aircraft's demonstrated climb performance for the conditions.
Frequently asked questions
How do I convert ft/nm to feet per minute?
Rate of climb = ground speed (kt) × gradient (ft/nm) ÷ 60. Dividing ground speed by 60 gives nautical miles per minute, and multiplying by the gradient gives the vertical feet climbed each minute.
What does a SID climb gradient like 250 ft/nm mean?
You must gain at least 250 ft of altitude for every nautical mile of ground track until the stated point. Enter 250 in gradient mode with your ground speed to see the equivalent rate of climb in fpm.
How is the gradient percentage calculated?
It is gradient in ft/nm divided by 60.76, because one nautical mile is 6076.12 ft, so a 1% slope rises 60.76 ft over one nautical mile.
Why does higher ground speed need a higher fpm?
The gradient is a fixed feet-per-mile requirement. The faster you cover ground, the more miles you fly each minute, so you must climb more feet per minute to hold the same gradient. Verify against your aircraft's performance charts.