In the network tab in activity monitor there is a read out of data usage showing sent and received in GB. What this dosnt tell you is over what time period this is, is it from a day, a week and month ?

This is from OSX Yosemite.

activity monitor screenshot

3 Answers 3


For the top two figures, since last boot; for the bottom two, current.

The little graph is 'since switching to that tab', as it doesn't log more than about 5 minutes of data.

This machine's been up 9 days, this looks about right for my standard usage -

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If I initiate a large download, the bottom figures become this [on a 150Mb/s line] -

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The graph scale auto-zooms, so the earlier few KB/s vanishes into a flat line.

Once the file has finished downloading, the top figures show the increase of about 2GB & the bottom pair goes back to being relatively idle

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Years later [2023], I have double-checked this. I downloaded ~10GB of data straight after boot, but before launching Activity Monitor. This confirms the top right figures are since boot.

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  • What about the Rcvd Bytes and Sent Bytes columns? Are they counting since boot, too?
    – Flimm
    Jul 1, 2016 at 13:49
  • That has to be counted since launch, not boot.
    – Tetsujin
    Jul 1, 2016 at 14:55
  • Since launch of Activity Monitor, or launch of the process?
    – Flimm
    Jul 1, 2016 at 14:57
  • It seems like it's counting network activity since the launch of Activity Monitor, not since the launch of the process.
    – Flimm
    Jul 4, 2016 at 9:04
  • I have a laptop with an uptime of 143 days but it shows Data received: 2.88 GB, which in my case would be a slow morning.
    – mspices
    Feb 13 at 12:51

The Data received and Data sent includes all network traffic. So if your machine is connected to a wi-fi network, but not the internet, it will show data sent between machines/devices. Also, if your machine is connected by ethernet to another machine, that's also counted. I figured this cos my machine (not connected to the internet) showed traffic of over 20GB, which tallies with the amount of data that I copied between this and another machine. So, this figure is not a count of internet usage data. As someone who occasionally has to use the iOS personal hotspot function, it's reassuring to know that this figure does not represent cellular data usage. For that, reset your iOS device's data counter.


The data received count is reset when you restart your computer

  • Tetsujin's answer already says that: "For the top two figures [i.e. data received (and data sent)], since last boot".
    – John N
    Mar 24, 2017 at 23:14
  • 1
    Tetsujin's answer says "It may be since launch of Activity Monitor". It's basically spending lots of words and pictures to say "I don't know".
    – ojs
    Apr 29, 2020 at 7:26
  • @ojs - I was reminded of this question recently & double-checked my initial observations. It's definitely since boot.
    – Tetsujin
    Jul 31, 2023 at 16:13
  • @Tetsujin ok, it looks a lot more convincing now
    – ojs
    Jul 31, 2023 at 18:56

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