This tool estimates a planet's surface gravity ($g$).

Important: Surface gravity depends on both the planet's **Mass (M)** and **Radius (R)**. Diameter alone is insufficient!

The core formula is: $$ g = G \frac{M}{R^2} $$

• $G$ (Gravitational Constant): $6.67430 \times 10^{-11} \text{ m}^3 \text{ kg}^{-1} \text{ s}^{-2}$
• Earth's Surface Gravity ($g_\oplus$): $9.80665 \text{ m/s}^2$

You can estimate by providing either:

1. The planet's **Mass** and **Diameter**.
2. The planet's **Diameter** and its **Average Density** (if mass is unknown, mass will be calculated as $M = \text{Density} \times \text{Volume}$).

Typical Average Densities:

• Rocky Planets (Earth, Mars): $3.9 - 5.5 \text{ g/cm}^3$
• Ice Giants (Uranus, Neptune): $1.3 - 1.6 \text{ g/cm}^3$
• Gas Giants (Jupiter, Saturn): $0.7 - 1.3 \text{ g/cm}^3$