When to use this calculator
Use a gravitational parameter appropriate to the central body. This speed applies to a circular orbit at the entered radius.
Explore the orbits & escape calculators for other questions in this topic. For a related calculation, use the Elliptical Orbit Eccentricity Calculator: Find orbital eccentricity from extreme orbital distances.
PUTTING IT INTO PRACTICE
Circular Orbit Speed: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Gravitational parameter μ (km³/s²) | 400,000 |
| Distance from body centre (km) | 10,000 |
| Result | 6.324555 km/s |
- Check the input labels and enter the example values above.
- Apply the relationship: Orbital speed = √(μ/radius).
- The result is 6.324555 km/s, rounded for display.
How to interpret your result
Radius is measured from the centre of the primary, not from its surface. Ignores atmospheric drag.
Use radius from the centre of the attracting body, not altitude above its surface. Choose the gravitational parameter of the correct primary. Drag, rotation and other bodies are excluded from these simple models.
Frequently asked questions
Can I use altitude directly as orbital radius?
No. Add the central body’s radius to altitude when a formula requires distance from its centre.
When is the circular orbit speed calculator useful?
Use a gravitational parameter appropriate to the central body. This speed applies to a circular orbit at the entered radius.
How do I use the circular orbit speed calculator?
Enter gravitational parameter μ (km³/s²), distance from body centre (km). The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
Orbital speed = √(μ/radius).
What should I check before using the result?
Radius is measured from the centre of the primary, not from its surface. Ignores atmospheric drag.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
Further reading
For background on this topic, see NASA: orbits and Kepler’s laws ↗. This is a topic reference, not an external review or endorsement of this tool.
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