Top-of-Descent Calculator

Calculate when to begin your descent with precision

Top-of-Descent (TOD)

Calculate when to begin your descent

Cruise Altitude

ft

Target Altitude

ft

Glide Angle

°

Ground Speed

kt

Buffer Distance

nm

Altitude to Lose

33,000ft

TOD Distance

103.6nm

Start Descent At

113.6nm

Time to TOD

22.2min

Required VS

1,486fpm

Drop per NM

318ft

At 3°, rule-of-thumb is VS ≈ GS × 5; this tool uses exact trigonometry.