Quick answer: If the internet is slow only on your Mac, the cause is usually a weak Wi-Fi signal, a VPN or iCloud Private Relay, or an app using bandwidth in the background. If every device is slow, it’s your router or your ISP. Start with the quick fixes: turn Wi-Fi off and on, pause your VPN, check Activity Monitor’s Network tab, and restart your router. To see exactly where a slowdown starts, a network monitor for Mac such as PeakHour measures latency to your router and to your ISP separately and keeps a history.

Step 1: Is it your Mac, your Wi-Fi, or your internet?

Spend two minutes on this before changing any settings. It tells you which fixes to try.

  1. Test another device. Run a speed test on your phone on the same Wi-Fi, next to the Mac.
  2. Test your Mac. Open Terminal and run networkQuality. It reports download, upload and a responsiveness rating. (More ways to test speed on a Mac →)
  3. Ping your router. Find its address in System Settings → Wi-Fi → Details… → TCP/IP → Router (often 192.168.1.1). Then run ping -c 20 192.168.1.1 in Terminal.
    • Router pings under ~5 ms and steady → your Wi-Fi is fine; the problem is further out.
    • Router pings high, jumpy, or with timeouts → the problem is Wi-Fi.

Fixes when only your Mac is slow

1. Turn Wi-Fi off and on (or restart your Mac)

Click Wi-Fi in the menu bar, turn it off, wait ten seconds and turn it back on. If your Mac has been awake for weeks, restart it (Apple menu → Restart).

2. Check your Wi-Fi signal

Hold Option and click the Wi-Fi icon. Check:

  • RSSI (signal): −30 to −67 dBm is good; below −70 dBm is weak.
  • Tx Rate: the link speed to your router. If it’s lower than your internet plan, Wi-Fi is your bottleneck.
  • Channel: shows whether you’re on 2.4 GHz, 5 GHz or 6 GHz.

If the signal is weak, move closer, remove obstacles (metal, walls, fish tanks), or join the router’s 5 or 6 GHz network. 2.4 GHz reaches further but is slower and more crowded.

3. Turn off VPN, iCloud Private Relay and content filters

These send all your traffic through another server, which adds distance and latency.

  • VPN: disconnect it in the VPN app or in System Settings → VPN, then test again.
  • iCloud Private Relay: System Settings → [your name] → iCloud → Private Relay. Turn it off, or turn it off just for this network by switching off Limit IP address tracking under Wi-Fi → Details….
  • Security or filtering apps (antivirus web shields, parental controls, ad-blocking DNS) can slow things down too. Pause them to test.

4. Find apps using your bandwidth

Open Activity Monitor → Network, then sort by Rcvd Bytes or Sent Bytes. Common causes:

  • iCloud Drive, Photos, Dropbox, Google Drive or OneDrive syncing
  • Backups (Time Machine to a network drive, Backblaze)
  • macOS or app updates downloading in the background
  • Browser tabs playing video

Pause or quit the app, then test again. For per-connection detail, run nettop in Terminal.

5. Forget the network and rejoin

Go to System Settings → Wi-Fi, click Details… next to your network, then choose Forget This Network. Rejoin it and enter the password again. While you’re in Details…, check Private Wi-Fi address: on some routers, setting it to Fixed or Off fixes slow or dropping connections.

6. Change your DNS servers

Slow DNS makes every page slow to start loading, even when your download speed is fine. In Wi-Fi → Details… → DNS, add 1.1.1.1 (Cloudflare) or 8.8.8.8 (Google). This won’t raise your Mbps, but it can make browsing feel faster.

7. Flush the DNS cache and renew your IP address

If some sites won’t load, or load the wrong page after a network change, clear the Mac’s DNS cache. In Terminal, run:

sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder

Enter your Mac’s password when asked (nothing appears as you type). Then renew your IP address from the router: System Settings → Wi-Fi → Details… → TCP/IP → Renew DHCP Lease.

8. Try Ethernet

Plug in with a cable (MacBooks need a USB-C to Ethernet adapter). If the Mac is fast on Ethernet and slow on Wi-Fi, you’ve confirmed Wi-Fi is the problem. Improve the signal, or add a mesh node near where you work.

9. Update macOS and run Wireless Diagnostics

Install updates in System Settings → General → Software Update; Apple fixes Wi-Fi bugs regularly. Then hold Option, click Wi-Fi, and choose Open Wireless Diagnostics. It checks for interference and saves a report you can share with support.

Last resort: reset the network configuration

In System Settings → Network, Control-click Wi-Fi and choose Delete Service. Add it back with … → Add Service, then restart. This clears corrupted settings without deleting any files by hand.

Fixes when every device is slow

1. Restart your modem and router, in order

Unplug the modem (and the router, if it’s a separate box). Wait 30 seconds. Plug the modem in first and wait until its lights settle, then plug in the router.

2. Check whether it’s your ISP, and when

If it’s slow every evening but fine in the morning, that’s usually congestion at your ISP. Check your ISP’s outage page, then keep a record: speed tests at different times, a packet loss test when calls or games stutter, or a monitor that logs latency and packet loss all day. PeakHour records latency to your router and to your ISP separately, so you can see whether a slowdown starts in your home or beyond it. It also sends a notification when the connection drops. That record makes a much stronger complaint to your ISP. How to track ISP performance on macOS →

3. Fix bufferbloat

If networkQuality reports Low responsiveness, or calls stutter whenever someone uploads or streams, your router is probably queuing too much traffic. Look for Smart Queue Management (SQM), QoS or Smart Queues in your router’s settings and turn it on.

4. Update router firmware and check the channel

Log in to your router (or its app) and install firmware updates. If you live near many other networks, pick a less crowded channel, or let the router choose one automatically.

5. Check whether you’ve outgrown your plan

Add up what your household does at the same time: 4K streams (~15 Mbps each), video calls, cloud backups. If your peak use is close to your plan speed, everything will feel slow. A bandwidth monitor for Mac that reads your router shows what the whole household uses at its busiest. Track your monthly usage →

Symptom → cause → fix

Symptom Likely cause Try
Only the Mac is slow Wi-Fi signal, VPN/Private Relay, background app Fixes 2–4 above
Slow on Wi-Fi, fast on Ethernet Wi-Fi signal or interference Move closer, 5/6 GHz, mesh
Everything slow in the evening ISP congestion Log it, contact your ISP
Calls lag when someone uploads Bufferbloat Turn on SQM/QoS
Pages slow to start, downloads fine DNS Change DNS
Keeps dropping, then comes back Wi-Fi, router or line Monitor with alerts to find the pattern

FAQs

Why is my internet slow on my Mac but fast on my phone?

The phone is usually closer to the router, on a different band, or not running a VPN, Private Relay or a background sync. Compare the two side by side, then check the Mac’s Wi-Fi signal (Option-click Wi-Fi) and Activity Monitor’s Network tab.

Why is my internet so slow on my Mac?

The most common causes are a weak Wi-Fi signal where the Mac sits, a VPN or iCloud Private Relay, and apps syncing or updating in the background. Work through Step 1 to find out which one it is before you change any settings.

How can I tell if the problem is my Mac or my internet provider?

Test a second device on the same network, then ping your router. If the router answers quickly and steadily but everything is slow, the problem is beyond your home: your modem, the line or your ISP. A monitor that records latency to your router and to your ISP separately, such as PeakHour, shows you which one it is over days, not just in one test.

Why did my Mac’s internet get slow after a macOS update?

After a major update, macOS re-indexes and re-syncs iCloud, which uses bandwidth for a few hours. If it’s still slow after a day, forget and rejoin your Wi-Fi network and check whether Private Relay or Private Wi-Fi Address settings changed.

What is mDNSResponder, and why is it using so much network?

mDNSResponder is the macOS service that handles DNS lookups and Bonjour (finding printers, AirPlay devices and other Macs). High usage usually means an app is making a lot of lookups, or a device on your network is flooding Bonjour traffic. Quit apps one at a time to find the cause, and restart the Mac. Don’t try to disable it: that breaks name lookups.

Why is my internet slower in the evening?

More people in your area are online, so your ISP’s network is busier. If speeds drop a lot every evening, record it for a week and share the results with your ISP.

Related: How to test internet speed on Mac · How to track ISP performance · Best bandwidth monitors for Mac