Glide Ratio Calculator

Work out glide ratio instantly with clear inputs, formula shown and shareable results.

About Glide Ratio Calculator

Glide ratio is horizontal distance divided by height lost in the same units, so it equals the aerodynamic lift-to-drag ratio when flown at the correct speed. A 4 nautical mile glide from 2,500 ft is about 9.7:1. Weight changes the best glide speed but not the ratio itself.

Formula

Glide ratio

L/D = horizontal distance / height lost (same units); angle = atan(1 / (L/D))

Worked example

With the default values below, Glide Ratio Calculator returns Glide ratio of 9.72. Change any input above and every figure here is recalculated in your browser.

Inputs used

Horizontal distance travelled: 4 nm
Height lost: 2,500 ft
Aircraft weight ratio to reference: 1 x

Results

Glide ratio: 9.72 ：1
Glide angle: 5.87 °
Height loss per nautical mile: 625 ft/nm
Equivalent lift-to-drag ratio: 9.72

Step by step

1Values used
2Glide ratio
3Glide ratio= 9.72 ：1
4Glide angle= 5.87 °
5Height loss per nautical mile= 625 ft/nm
6Equivalent lift-to-drag ratio= 9.72

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Aviation results are planning estimates only. Always verify take-off, landing, fuel, weight and balance figures against the certified Aircraft Flight Manual, current performance charts and applicable aviation regulations before flight.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Aviation results are planning estimates only. Always verify take-off, landing, fuel, weight and balance figures against the certified Aircraft Flight Manual, current performance charts and applicable aviation regulations before flight.

Frequently Asked Questions

Why does weight not change the glide ratio?

A heavier aircraft glides at the same angle but at a higher speed and higher sink rate, so it covers the same distance in less time.

What ratios are typical?

Around 9:1 for a light single, 15-18:1 for a modern jet transport in clean glide, and 40:1 or more for a competition glider.