Your internet feels slow, but you’re not sure why. Before you call your ISP or buy a new router, you can diagnose the problem yourself. A few simple tests will tell you whether the issue is on your end, your ISP’s end, or somewhere else entirely.

Start with a speed test

First, establish what you’re actually getting. Apple added a command line tool called networkQuality in macOS Monterey:

networkQuality

This tests upload speed, download speed, and responsiveness (latency under load). Run it a few times and note the results. Compare to what you’re paying for. If your plan promises 100 Mbps down and you’re getting 95, that’s normal. If you’re getting 20, something is wrong.

You can also use web-based speed tests like fast.com or speedtest.net. Run a few from different services. If results vary wildly, there might be congestion on routes to specific servers.

Test at different times of day. Speeds that are fine at 10am but terrible at 8pm suggest network congestion, either in your neighborhood or at your ISP.

Check your local connection

Slow internet often starts at home. Your Wi-Fi might be the bottleneck, not your ISP.

If you’re on Wi-Fi, try connecting via Ethernet cable directly to your router. Run the speed test again. If speeds improve dramatically, your Wi-Fi is the problem. If speeds stay the same, the issue is upstream.

For Wi-Fi troubleshooting, Option-click the Wi-Fi icon in your menu bar and select “Open Wireless Diagnostics.” Use the scan feature to see all nearby networks. Look at what channels they’re using. If your network and several neighbors are all on channel 6, you’re competing for airtime. Changing your router’s channel can help.

Signal strength matters too. The further you are from your router, the slower your connection. Walls, floors, and appliances create interference. Moving closer to the router or repositioning it can make a significant difference.

Ping test for basic connectivity

Ping measures the round-trip time for packets to reach a destination and return. High ping times indicate latency, which makes everything feel sluggish.

Start by pinging your router:

ping -c 10 192.168.1.1

Replace 192.168.1.1 with your router’s actual IP (you can find it in System Settings > Network > Wi-Fi > Details > TCP/IP). If ping times to your own router are high (above 10ms) or inconsistent, there’s a problem with your local network.

Next, ping something on the internet:

ping -c 10 8.8.8.8

This pings Google’s DNS server. Times under 50ms are good for most locations. If pings to your router are fast but pings to the internet are slow, the problem is between your router and the destination.

Look for packet loss too. If the ping summary shows packets lost, that’s a sign of a flaky connection somewhere.

Traceroute for path analysis

Traceroute shows every hop between your Mac and a destination. It reveals where slowdowns occur.

traceroute google.com

Each line is a router along the path. The three numbers at the end are response times in milliseconds for three separate probes.

Look for sudden jumps in latency. If hops 1-3 are all under 20ms and then hop 4 jumps to 200ms, there’s congestion or a problem at that point.

The first few hops are your local network and ISP. If high latency appears there, the problem is close to home. High latency on distant hops is harder to fix because those networks aren’t yours to control.

Asterisks (* * *) mean a router didn’t respond to probes. This isn’t necessarily a problem. Many routers ignore traceroute packets. If the route continues beyond the silent hop, traffic is still flowing.

DNS issues

Slow DNS resolution makes the internet feel laggy. Every time you visit a new site, your browser has to look up the IP address. If that lookup takes a long time, page loads stall.

Test DNS speed:

time dig google.com

The “Query time” line shows how long the lookup took. Under 50ms is good. Over 200ms is slow.

If DNS is slow, try switching DNS servers. Your ISP’s default DNS might be overloaded or poorly maintained.

To use Google’s DNS (8.8.8.8 and 8.8.4.4) or Cloudflare’s DNS (1.1.1.1 and 1.0.0.1), go to System Settings > Network > Wi-Fi > Details > DNS. Remove existing entries and add new ones.

After changing DNS, flush your Mac’s DNS cache:

sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder

Run the dig test again and see if times improve.

Check for background activity

Your Mac might be using bandwidth you don’t know about. Software updates, cloud sync services, and background apps all consume bandwidth.

Open Activity Monitor (Applications > Utilities > Activity Monitor) and click the Network tab. Sort by “Sent Bytes” or “Rcvd Bytes” to see what’s using the most bandwidth.

Common bandwidth hogs include iCloud syncing large photo libraries, Dropbox or Google Drive uploading files, Time Machine backing up over the network, software updates downloading in the background, and browser tabs with auto-refreshing content.

If something is consuming significant bandwidth, pause it or schedule it for off-hours.

Router and modem checks

Your networking equipment might be the problem. Routers and modems are small computers that can slow down, run out of memory, or develop bugs.

Restart your modem and router. Unplug them, wait 30 seconds, plug in the modem first and wait for it to sync, then plug in the router. This clears cached state and often resolves mysterious slowdowns.

Check for firmware updates. Router manufacturers release updates that fix bugs and improve performance. Log into your router’s admin interface (usually at 192.168.1.1 or similar) and look for update options.

If your router is more than five years old, it might not support modern Wi-Fi standards. Upgrading to a Wi-Fi 6 router can significantly improve speeds, especially with multiple devices.

ISP issues

Sometimes the problem really is your internet provider. Before calling support, gather evidence.

Run speed tests at different times and keep records. Note when slowdowns happen. Check your ISP’s status page or social media for reported outages.

When you call, you’ll have data to share. “My speeds drop to 10 Mbps every evening between 7pm and 10pm” is more useful than “it’s slow sometimes.” ISPs can check their equipment for issues on your line and may send a technician if needed.

If slowdowns affect specific sites but not others, the problem might be peering. Your ISP’s connection to certain networks might be congested. This is harder to fix, but documenting specific affected sites helps.

Systematic approach

Work through these steps in order:

Run a speed test to establish baseline
Test wired vs wireless to isolate Wi-Fi issues
Ping your router to check local network health
Ping external servers to check internet connectivity
Run traceroute to find where delays occur
Check DNS speed and try alternative servers
Look for bandwidth-consuming apps on your Mac
Restart networking equipment
Contact ISP with documented evidence if needed

Each step narrows down where the problem lives. You might find it’s your Wi-Fi signal, a misconfigured DNS, or actually your ISP’s fault. Knowing which lets you fix it or at least know who to blame.

Tools that help

macOS includes everything you need for basic troubleshooting. Terminal has ping, traceroute, and dig. Activity Monitor shows network usage. Wireless Diagnostics analyzes Wi-Fi.

The inconvenience is switching between tools and interpreting text output. If you troubleshoot network issues regularly, a unified tool saves time.

NetUtil puts ping, traceroute, DNS lookup, and other diagnostics in one interface. You can run tests quickly without remembering command syntax, and results display in a format that’s easy to scan.

Whether you use built-in tools or something else, the process is the same. Test systematically, isolate the problem, and fix what you can. Slow internet has causes, and those causes are discoverable.