Time and distance to climb calculator
A climb uses up time and route distance before the cruise even starts. On a short leg the climb can be most of the flight, which is why leg planning that ignores it comes out wrong.
Calculator
This is an educational and planning aid. Use current official weather, your aircraft flight manual, and the rules that apply to your flight before you act on any figure here. See the aviation disclaimer.
What the result means
The time is how long the climb takes at the rate you entered. The distance is how far along the ground you travel while doing it.
The average gradient is shown as a cross check, and it is the figure to compare against any published departure requirement.
When this is useful
- Planning a leg where the cruise segment needs to be separated from the climb.
- Working out whether you will reach a required altitude before a boundary, an airway joining point, or high ground.
- Estimating the fuel penalty of a climb, since the higher climb fuel flow applies for this long.
How it is calculated
Time is the altitude to gain divided by the rate of climb. Distance is that time multiplied by groundspeed. Both are straightforward once the units are consistent, which the calculator handles.
time = altitude to gain / rate of climb, distance = groundspeed x time
Worked example
- Altitude to gain
- 6,000 ft
- Planned rate of climb
- 600 ft per minute
- Average groundspeed
- 100 kt
The climb takes 10 minutes and covers 16.7 NM over the ground.
Check: 6,000 ft at 600 ft per minute is exactly 10 minutes. At 100 kt you cover 100 NM in an hour, so in 10 minutes you cover one sixth of that, 16.7 NM. The resulting 360 ft per NM also matches the independent climb gradient calculation for the same inputs.
Limitations
- It uses one average rate of climb. A real aircraft climbs fastest low down and slows as the air thins, so a single figure flatters a climb to high altitude. Splitting a long climb into segments gives a far better answer.
- Groundspeed also increases through a climb as true airspeed rises, which this does not model.
- It assumes a continuous climb with no level segment, which ATC may not give you.
Common mistakes
- Entering the target altitude rather than the altitude to gain. This wants the difference between the two.
- Using a sea level rate of climb for a climb to high altitude.
- Using true airspeed instead of groundspeed, which gives the wrong distance in any wind.
Sources
- Pilot's Handbook of Aeronautical Knowledge, aircraft performance , US Federal Aviation Administration