Top of Descent
Find the distance to start your descent, the required rate of descent, and the time it takes — from cruise to a target altitude.
Start descent
100.5 nm
Required rate
2,229 fpm
Descent time
14.4 min
Begin descent about 100 nm before the target altitude at a 3° path. The 3-to-1 rule of thumb gives ~96 nm. Adjust for wind, speed changes and ATC.
How this works
Distance is altitude-to-lose divided by the descent gradient (a 3° path ≈ 318 ft per nautical mile); required rate of descent follows from your groundspeed. The quick mental version is the 3-to-1 rule: 3 nm per 1,000 ft to lose.
For planning and familiarisation only. Fly ATC instructions and your aircraft's published procedures. Not for navigation or flight planning — always verify against official current sources.