Roche Limit Calculator
Calculate the Roche limit — the minimum orbital distance before a satellite is torn apart by tidal forces from a larger body.
Use the Roche Limit Calculator
Primary Body
Satellite
Enter primary body and satellite parameters,
then click Calculate.
Roche Limit Distance
Fluid bodyKilometers
Earth Radii
AU
Calculation Details
Summary
Calculate the Roche limit — the minimum orbital distance before a satellite is torn apart by tidal forces from a larger body.
How it works
- Enter the primary body mass (e.g., Earth, Jupiter) and its equatorial radius.
- Enter the satellite density — the bulk density of the smaller orbiting body.
- Choose the formula: rigid sphere (conservative lower bound) or fluid body (real-world upper bound).
- Click Calculate to get the Roche limit distance in kilometers, Earth radii, and AU.
- Compare the result against a known moon or ring system to see whether it lies inside the disruption zone.
Use cases
- Determine why Saturn's rings exist inside its Roche limit.
- Check whether a proposed orbit for a small moon is stable.
- Study tidal disruption in binary star systems.
- Visualize how density affects the Roche limit for different satellite compositions.
- Explore the difference between the rigid-sphere and fluid-body approximations.
- Educational demonstrations of planetary science and orbital mechanics.
Frequently Asked Questions
Last updated: 2026-09-19 ·
Reviewed by Nham Vu