Show FPS in Unity

ShowFPS.cs

using UnityEngine;
using System.Collections;

public class ShowFPS : MonoBehaviour
{

    const float fpsMeasurePeriod = 0.5f;
    private int m_FpsAccumulator = 0;
    private float m_FpsNextPeriod = 0;
    private int m_CurrentFps;
    const string display = "{0} FPS";


    void Start()
    {
        m_FpsNextPeriod = Time.realtimeSinceStartup + fpsMeasurePeriod;
    }

    void Update()
    {
        // measure average frames per second
        m_FpsAccumulator++;
        if (Time.realtimeSinceStartup > m_FpsNextPeriod)
        {
            m_CurrentFps = (int)(m_FpsAccumulator / fpsMeasurePeriod);
            m_FpsAccumulator = 0;
            m_FpsNextPeriod += fpsMeasurePeriod;
        }
    }

    void OnGUI()
    {
        GUILayout.Label(string.Format(display, m_CurrentFps));
    }

}