This article outlines Roblox physical units and how they convert to metric units. Understanding units is useful whenever you work with physics, as in the following examples:
- Customizing your experience's gravity, jump height/power, and walk speed in the World tab of Game Settings.
- Tuning linear/angular velocities, forces, torques, stiffness, and damping of mechanical constraints and mover constraints.
- Adjusting the density of custom materials.
Unit Conversions
In general, you can use the conversions in the following table to relate Roblox's primary units for time, length, and mass to their metric counterparts.
| Unit | Roblox | Metric |
|---|---|---|
| Time | 1 second | 1 second |
| Length | 1 stud | 28 cm |
| Mass | 1 RMU* | 21.952 kg |
Importance of Unit Consistency
Internally, the Roblox physics engine does not use unit conversions. You're free to define your own unit interpretations for studs (length) and RMUs (mass), but these should be used in a consistent manner throughout the experience. For example, if you decide that one stud equals one foot (30.483 cm), the unit density of water implies an RMU is equal to 62.4 lbs (28.3 kg):
1 (g/cm³) × (30.48³ cm³/ft³) = 28,317 (g/ft³) × (0.00220462 lbs/g) = 62.4 (lbs/ft³) = 1 (RMU/stud³)
Overall, it's recommended that you use standard Roblox units because it makes an experience work as expected in all scenarios, such as compatibility with VR controls.