Convert between horizontal, vertical, and diagonal field of view angles. Select a VR headset preset or enter custom sensor dimensions. Get ready-to-use values for Unity, Unreal Engine, and Godot.
| Headset | H FoV | V FoV | Diag FoV | Resolution |
|---|
Field of View (FoV) is the extent of the observable world visible through the headset lenses at any moment. A wider FoV creates a more immersive "window" effect, while a narrow FoV can feel like looking through binoculars. Most standalone HMDs are around 100°–120° horizontal.
It's a historical convention difference. Unity's Camera.fieldOfView property is the vertical angle; changing the aspect ratio automatically adjusts horizontal FoV. Unreal Engine's FOV setting is horizontal. This calculator converts between both so you can set the correct value in your engine.
Diagonal FoV measures the angle from corner to corner of the display. It's often cited in lens/camera specs and is always larger than either H or V FoV. You can calculate it from H and V using the formula: 2 × atan(√(tan²(H/2) + tan²(V/2))).
Many HMDs have asymmetric projection planes — the inner (nasal) FoV is smaller than the outer (temporal) FoV per eye, which is why total horizontal FoV often exceeds simple doubling of per-eye values. This calculator uses symmetric approximations; check your headset SDK for precise projection matrices.