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Satellite Coverage Area Calculator

Work out satellite coverage area instantly with clear inputs, formula shown and shareable results.

About Satellite Coverage Area Calculator

A satellite's footprint is a spherical cap whose extent depends on altitude and the minimum usable elevation angle. At 550 km with a 25 degree mask the central angle is 13.4 degrees, giving a ground radius of about 1490 km and 6.8 million square kilometres - roughly 1.4% of Earth's surface, which is why megaconstellations need thousands of satellites.

Formulas

Nadir angle

eta = arcsin((Re / Rs) cos(elevation))

Central angle and cap area

lambda = 90 - elevation - eta; area = 2 pi Re^2 (1 - cos lambda)

Worked example

With the default values below, Satellite Coverage Area Calculator returns Ground Coverage Area of 2.77409 × 10⁶. Change any input above and every figure here is recalculated in your browser.

Inputs used

Satellite altitudeminimum 1 km
550 km
Minimum elevation angleaccepts 0–89 deg
25 deg

Results

Ground Coverage Area
2.77409 × 10⁶ km2
Earth Central Angle
8.46 deg
Coverage Radius On The Ground
940.5 km
Share Of Earth's Surface
0.544%

Step by step

  1. 1Values used
  2. 2Nadir angle
  3. 3Central angle and cap area
  4. 4Ground Coverage Area= 2,774,090.00000 km2
  5. 5Earth Central Angle= 8.46 deg
  6. 6Coverage Radius On The Ground= 940.5 km
  7. 7Share Of Earth's Surface= 0.544

Assumptions and limits

  • The result is derived only from the 2 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 5 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

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

Frequently Asked Questions

Why impose a minimum elevation angle?

Because low angles mean long atmospheric paths, multipath and terrain blocking. Typical masks are 10-25 degrees for reliable links.

How many satellites cover the globe?

It depends on altitude: three at geostationary height, but hundreds to thousands in low Earth orbit.

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