Calculate the orbital period for any body orbiting a central mass. Includes solar system verification, unit conversions, and binary system mode.
The orbital period is the time it takes for a celestial body to complete one full orbit around another body. It is determined by the mass of the central body and the orbital distance, following directly from Kepler's Third Law generalized by Newton: T = 2π√(a³/GM).
From the 92-minute orbit of the International Space Station to the 165-year orbit of Neptune, orbital periods span an extraordinary range. Understanding how period relates to distance and mass is essential for satellite engineering, space mission planning, and exoplanet characterization.
This calculator computes the orbital period from the central body's mass and the orbital distance, supports multiple mass and distance units, handles binary systems, and verifies results against the known orbital periods of all solar system planets and the Moon. An interactive comparison chart and period unit conversion table provide additional context.
Use the preset examples to load common values instantly, or type in custom inputs to see results in real time. The output updates as you type, making it practical to compare different scenarios without resetting the page.
This calculator provides instant orbital period computations for any gravitational system, from Earth satellites to exoplanets. The built-in solar system verification table and multiple unit options make it both a learning tool and a practical reference for students, engineers, and astronomy enthusiasts.
This tool is designed for quick, accurate results without manual computation. Whether you are a student working through coursework, a professional verifying a result, or an educator preparing examples, accurate answers are always just a few keystrokes away.
Orbital period: T = 2π × √(a³ / (GM)), where T is the period in seconds, a is the semi-major axis in meters, G = 6.674 × 10⁻¹¹ m³/(kg·s²), and M is the central body mass in kilograms. Orbital velocity: v = 2πa / T.
Result: Period ≈ 92.4 minutes
The ISS orbits at about 6,771 km from Earth's center (400 km altitude). At this distance, the orbital period is about 92 minutes, completing ~15.5 orbits per day.
Use consistent units throughout your calculation and verify all assumptions before treating the output as final. For professional or academic work, document your input values and any conversion standards used so results can be reproduced. Apply this calculator as part of a broader workflow, especially when the result feeds into a larger model or report.
Most mistakes come from mixed units, rounding too early, or misread labels. Recheck each final value before use. Pay close attention to sign conventions — positive and negative inputs often produce very different results. When working with multiple related calculations, keep intermediate values available so you can trace discrepancies back to their source.
Enter the most precise values available. Use the worked example or presets to confirm the calculator behaves as expected before entering your real data. If a result seems unexpected, compare it against a manual estimate or a known reference case to catch input errors early.
Two factors: the mass of the central body and the orbital distance. Greater mass means a shorter period at the same distance, and greater distance means a longer period around the same mass.
For most practical cases no — only the central body mass matters. For binary systems where both masses are comparable, the total system mass is used.
An orbit with a period of exactly 24 hours (86,400 seconds) at about 35,786 km altitude above Earth's equator. Satellites in this orbit appear stationary from the ground. Understanding this concept helps you apply the calculator correctly and interpret the results with confidence.
At just 400 km altitude (6,771 km from Earth's center), the ISS is close enough that Earth's. Understanding this concept helps you apply the calculator correctly and interpret the results with confidence. gravity produces a very short orbital period of about 92 minutes.
Yes. Enter the host star's mass in solar masses and the orbital distance in AU to compute any exoplanet's orbital period.
No. The orbital period depends only on the semi-major axis, not the eccentricity. A circular and a highly elliptical orbit with the same semi-major axis have the same period.