---
title: "Which app is using my bandwidth on Mac? Activity Monitor and nettop · Kilobat Guides"
url: "https://kilobat.app/guides/which-app-uses-bandwidth"
description: "Find the app or process that uses your Mac's internet connection with Activity Monitor and nettop in Terminal, then pause or limit it."
---

Websites and speed

# Find which app uses your bandwidth on a Mac

Activity Monitor and `nettop` show which processes send and receive data. Use them to find a backup, sync or update that fills the connection.

Applies to: All current macOS versions. · Checked: 29 October 2026

## Symptoms

- The connection is slow, and you do not know why.
- Upload activity is high when you do not upload anything.
- A hotspot or data plan runs out fast.

## Likely causes

- **Cloud sync and backups.** Photo libraries, cloud drives and backups move large amounts of data in the background.
- **Software updates.** macOS and apps download updates on their own.
- **Helper processes.** Apps often move data through helper processes with different names.
- **System download services.** macOS services download on behalf of apps, so the app name does not always show.

## How to check

1. Open Activity Monitor from Applications > Utilities. Click Network.
2. Click a column heading to sort the processes by data sent or received.
3. Look at the bottom of the window. It shows the total data received and sent, and the rate per second.
4. To show network activity in the Dock icon, choose View > Dock Icon > Show Network Usage.
5. In Terminal, show a live list of processes with their network traffic. Press q to quit.

   ```
   nettop -P
   ```
6. To show only the changes since the last update, add `-d`.

   ```
   nettop -P -d
   ```
7. For one sample as comma-separated values, use `-L 1`.

   ```
   nettop -P -L 1 -J bytes_in,bytes_out
   ```

## How to fix it

1. Pause the app's sync or backup from its own menu or settings.
2. Quit the app if you do not need it now.
3. On a hotspot, turn on Low Data Mode for that network. See [Use Low Data Mode on a Mac](https://kilobat.app/guides/low-data-mode-mac).
4. Schedule large updates for a time when you do not need the connection.

## With Kilobat

1. Kilobat shows live upload and download for every app in the menu bar. Helpers are grouped under their app. This is free.
2. The CLI shows the same live view. Press s to sort and / to search.

   ```
   kilobat status --watch
   ```
3. To see one app's traffic over a day, use `bandwidth`. Kilobat records history while the app runs.

   ```
   kilobat bandwidth "Google Chrome" day
   ```
4. To see the sockets of one process, use `destinations`.

   ```
   kilobat destinations --pid 1234
   ```
5. History in the app needs Pro. See [See which app uses data on a hotspot](https://kilobat.app/guides/recipes/hotspot-data-by-app).

## Questions

**Why does Activity Monitor show a process I do not know?**

Many apps use helper processes, and macOS services download for apps. Search for the process name, or look at its path.

**Does nettop need an administrator password?**

No. Any user can run `nettop`.

## Sources

- [Apple Support: View network activity in Activity Monitor on Mac](https://support.apple.com/guide/activity-monitor/view-network-activity-actmntr1006/mac)
- nettop(1), man page installed with macOS 27.2

Sources checked on 29 October 2026. Man pages are the ones installed with macOS; open one with `man <name>` in Terminal.

## Related guides

- [See which app uses data on a hotspot](https://kilobat.app/guides/recipes/hotspot-data-by-app): Kilobat shows the upload and download of each app on your Mac.
- [Mac uses Personal Hotspot data in the background](https://kilobat.app/guides/hotspot-background-data): A Mac on a phone hotspot can use a lot of data with no action from you.
- [Slow internet on a Mac: find which part is slow](https://kilobat.app/guides/slow-internet-mac-cause): A slow connection has many possible causes.
- [See where your apps connect](https://kilobat.app/guides/recipes/see-where-apps-connect): Kilobat shows the open connections of each app and the country where each address is registered.
- [Use Low Data Mode on a Mac](https://kilobat.app/guides/low-data-mode-mac): Low Data Mode tells macOS and apps to use less data on one Wi-Fi network.
- [What is nsurlsessiond on Mac?](https://kilobat.app/guides/what-is-nsurlsessiond): nsurlsessiond is part of macOS.