---
title: mass
framework: spritekit
role: symbol
role_heading: Instance Property
path: spritekit/skphysicsbody/mass
---

# mass

The mass of the body, in kilograms.

## Declaration

```swift
var mass: CGFloat { get set }
```

## Mentioned in

Configuring a Physics Body

## Discussion

Discussion The actual unit is arbitrary as long as relative masses of objects are consistent throughout the game. The mass of the body affects its momentum as well as how forces are applied to the object. The mass and density properties are interrelated. When you change the value of either property, the other property’s value is automatically recalculated to be consistent. The default value is based on the size of the physics body and the body’s default density.

## See Also

### Defining a Physics Body’s Physical Properties

- [Configuring a Physics Body](spritekit/configuring-a-physics-body.md)
- [density](spritekit/skphysicsbody/density.md)
- [area](spritekit/skphysicsbody/area.md)
- [friction](spritekit/skphysicsbody/friction.md)
- [restitution](spritekit/skphysicsbody/restitution.md)
- [linearDamping](spritekit/skphysicsbody/lineardamping.md)
- [angularDamping](spritekit/skphysicsbody/angulardamping.md)