Which device is using my bandwidth?

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Hello,

In the past days we have seen that my laptop has very slow internet connection. I got in touch with the ISP support and they told me that our bandwidth utilization was maxed out. They even showed me a graph about this. But we don't have any devices actively downloading stuff. Is there a way to scan my home network and identify which is the bandwidth utilization for each one of the devices I have connected in my home? We mainly use TVs, AppleTV, Roku, Alexa, FireTV, iPhones, iPads and Windows computers. I need to find out the culprit! Thanks!