# How do you guys calculate when to descend?

Whenever I’m at cruise, I have to guesstimate when to start descending, but whenever I watch a grade 4 or 5 they always descend perfectly. What should I be doing?

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From NM.NM away from destination times 3

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Welcome to the forum! Have a read of the tutorials section to help you out! Also remember to have a search for topics before asking a question as this is a topic that has been discussed many times.

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You may also want to check out this one. Its similar to what @David_Lockwood replied but its a different thread.

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Could you reword that? This is a question that I am also looking for an answer for.

Simpler, 15’000ft* = 50 nm

25’000 = 80 nm

34’000 = 110 nm

*same for 16’000ft for exemple

With a 1800ft/min decent at 250 kts airspeed

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When altitude × 3 = distance - 5, I descend at ground speed × 5, e.g 15,000 × 3 = 45, then + 5 as a buffer, and 300GS × 5 is 1500FPM. Simple

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Or you can use this app here which has a descent calculator in it .

( Sorry for self advertising :) )

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