You can use devtools-for-devtools. Switch devtools to detached window mode (click devtools settings icon, click "undock" icon). Next time you can simply press Ctrl-Shift-D to toggle the mode. Invoke devtools-for-devtools by pressing Ctrl-Shift-i display FPS of all frames: UI.panels.timeline._flameChart._model._frameModel._frames.slice(1).map(f => +(1000 / f.duration).toFixed(1)) display the average FPS: +UI.panels.timeline._flameChart._model._frameModel._frames.slice(1).map(f => 1000 / f.duration).reduce((avg, fps, i) => (avg*i + fps) / (i+1), 0).toFixed(1) You can save this code as snippets in devtools Snippets panel and invoke it after step 2 above.

I d like to thank @wOxxOm for pointing out how to access DevTools for DevTools in the answer above. However, the code given to calculate average FPS was not quite right. For example, if there s a frame that takes one second to render, then that frame s fps is one. If there is another frame that takes (1000 / 60) ms to render, then that frame s fps is 60. The original code would give an average fps of (60 + 1) / 2 for these two frames, which is incorrect. The correct average fps is the total number of frames divided by the total duration. In this example, it is 2 / (1 + 1 / 60) fps. One way to implement this is: function averageFps() { let frames = UI.panels.timeline._flameChart._model._frameModel._frames; let duration = (frames[frames.length - 1].endTime - frames[0].startTime) / 1000; let average = frames.length / duration return +average.toFixed(2); }

Just a quick note that the API seems to have changed slightly for this, so the new code to accomplish this is now: let frames = UI.panels.timeline.flameChart.model.frameModelInternal.frames; let frameSet = []; let startTimeMs = UI.panels.timeline.flameChart.model.window().left; let endTimeMs = UI.panels.timeline.flameChart.model.window().right; let minFPS = 1000; let maxFPS = -1; let totalFPS = 0; for (let frameIdx in frames) { let frame = frames[frameIdx]; if (frame.startTime >= startTimeMs && endTimeMs >= frame.endTime) { frameSet.push(frame); let frameRate = (16.0/frame.duration) * 60; if (maxFPS < frameRate) { maxFPS = frameRate; } if (minFPS > frameRate) { minFPS = frameRate; } totalFPS += frameRate; } } console.log(`Total Frames: ${frameSet.length}`); console.log(`Min FPS: ${minFPS}`); console.log(`Max FPS: ${maxFPS}`); console.log(`Average FPS: ${totalFPS / frameSet.length}`);

Updated @Daniel Le s solution that considers currently selected range var startTime = UI.panels.timeline._flameChart._model._window.left; var endTime = UI.panels.timeline._flameChart._model._window.right; var frames = UI.panels.timeline._flameChart._model._frameModel._frames .filter(frame => (frame.startTime > startTime) && (frame.endTime < endTime)); var duration = (frames[frames.length - 1].endTime - frames[0].startTime) / 1000; var average = frames.length / duration console.log(+average.toFixed(2));

Updated code: display FPS of all frames: UI.panels.timeline.flameChart.model .frameModel().frames.slice(1).map(f => +(1000 / f.duration).toFixed(1)) display the average FPS: UI.panels.timeline.flameChart.model.frameModel() .frames.slice(1).map(f => 1000 / f.duration) .reduce((avg, fps, i) => (avg*i + fps) / (i+1), 0).toFixed(1)

The devtools for devtools is great! But your average does not take into account the duration of each frame nor the dropped or idle frames, given these durations [16,16,160] your code will report an average of 43.75 FPS, if you measure the weighted average correctly the FPS is 15.62. // const frames = UI.panels.timeline.flameChart.model.frames().filter(({ idle }) => !idle); const frames = [{ duration: 16 }, { duration: 16 }, { duration:160 }] const totalDuration = frames.reduce((total, { duration }) => (total + duration), 0); const weightedFps = frames.map(f => [f.dropped ? 0 : 1000 / f.duration, f.duration]) .reduce((avg, [fps, duration]) => avg + (fps * (duration / totalDuration)), 0); console.log(weightedFps);

This worked for me in Chrome: Open the dev tool : CTL+Shift+i Then Display it as detached : Next, Select "Rendering": Check Frame Rendering Stats: Start recording the performances Get the results graphically: