Fix Slow Wi-Fi on MacBook

Confirm the Problem Is Your MacBook

Run a speed test on your MacBook, then immediately run one on another device (iPhone, iPad, another laptop) on the same Wi-Fi network. If other devices are significantly faster, the problem is your Mac. If all devices are slow, the issue is your router or ISP and this guide won't help — check the router troubleshooting guides instead.

Fix 1: Check Activity Monitor for Bandwidth Hogs

Before changing settings, see what's actually consuming your bandwidth:

1. Open Activity Monitor (Spotlight search → Activity Monitor)
2. Click the Network tab
3. Sort by Bytes Sent or Bytes Received (click the column header)

Common bandwidth consumers on Mac: Time Machine backups, iCloud Drive syncing large files, Spotlight indexing after a macOS update, App Store downloading updates, or backup software like Backblaze or Dropbox syncing. Pause or reschedule these and test again.

Fix 2: Change DNS to a Faster Server

Slow DNS resolution causes web pages to feel slow even when download speed is fine. macOS often inherits slow ISP DNS settings:

1. Go to System Settings → Network → Wi-Fi
2. Click Details next to your connected network
3. Click the DNS tab
4. Click + and add 1.1.1.1 (Cloudflare)
5. Add a second entry: 1.0.0.1
6. Remove any existing DNS entries by selecting them and clicking -
7. Click OK, then Apply

Also flush the DNS cache in Terminal: sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder

Fix 3: Remove and Re-Add Your Wi-Fi Network

A stale or corrupted network profile can cause persistent slow connections:

1. Go to System Settings → Network → Wi-Fi → Details
2. Click Forget This Network
3. Reconnect by selecting your network from the Wi-Fi menu and entering your password

This forces macOS to build a fresh connection profile and often results in connecting to the faster 5 GHz band if your router broadcasts both bands on the same SSID.

Fix 4: Renew DHCP Lease

An old or conflicting DHCP lease can sometimes cause routing issues that slow down connections:

1. Go to System Settings → Network → Wi-Fi → Details → TCP/IP
2. Click Renew DHCP Lease
3. Click OK and test your speed again

Fix 5: Use Wi-Fi Diagnostics

macOS has a built-in Wi-Fi Diagnostics tool that can identify signal, channel, and interference problems:

1. Hold Option and click the Wi-Fi icon in the menu bar
2. Select Open Wireless Diagnostics
3. Click Continue and let it run a full scan
4. Review the Summary for recommendations about channel interference, noise levels, or signal strength

If Wireless Diagnostics recommends a channel change, log into your router admin panel and apply it.

Fix 6: Check Your Preferred Network Order

macOS remembers all Wi-Fi networks you've connected to and has a priority order. If you have multiple saved networks (home, office, neighbor's network you connected to once), macOS might connect to a weaker one:

1. Go to System Settings → Network → Wi-Fi
2. Scroll down to find your preferred networks list
3. Remove networks you no longer use — especially any with similar names to your main network

Fix 7: Reset Network Configuration Files

If all else fails, corrupted macOS network preference files can cause persistent issues. This is more involved but effective for stubborn problems:

1. Open Finder and press Cmd+Shift+G
2. Type /Library/Preferences/SystemConfiguration/ and press Enter
3. Delete these files (move to Trash): com.apple.airport.preferences.plist, com.apple.network.identification.plist, NetworkInterfaces.plist, preferences.plist
4. Restart your Mac — macOS will recreate these files fresh on startup
5. Reconnect to your Wi-Fi network

Note: This removes all saved Wi-Fi passwords. Have your passwords ready before doing this.

Frequently Asked Questions

Why is my MacBook Wi-Fi slow but my iPhone is fast on the same network?

The problem is device-specific. Common causes: MacBook connected to 2.4 GHz instead of 5 GHz, stale network profile, slow DNS, or background macOS processes (Time Machine, iCloud, Spotlight) consuming bandwidth.

How do I reset Wi-Fi settings on a Mac?

Go to System Settings → Network → Wi-Fi → Details → Forget This Network. For deeper reset, delete preference files in /Library/Preferences/SystemConfiguration/ and restart.

How do I change DNS on a MacBook?

System Settings → Network → Wi-Fi → Details → DNS tab → + button → add 1.1.1.1 and 1.0.0.1 → remove existing entries → OK → Apply.

Can background macOS processes slow down Wi-Fi?

Yes. Time Machine, iCloud Drive sync, Spotlight indexing after updates, and App Store downloads can all saturate your connection. Check Activity Monitor → Network tab to see what's consuming bandwidth.