Screen.currentResolution

Description

The current screen resolution (Read Only).

Returns the current screen resolution (read only). If the player is running in windowed mode, this returns the current dimensions of the game window in pixels and the display refresh rate. If you are working with VR devices, use VRSettings.eyeTextureWidth and VRSettings.eyeTextureHeight instead.

using UnityEngine;

public class Example : MonoBehaviour
{
    void Start()
    {
        print(Screen.currentResolution);
    }
}