Slow internet is frustrating. But before you call your ISP or upgrade your plan, it’s worth diagnosing the actual cause — because slow internet has many possible causes, and the fix is completely different depending on which one applies to you.
Step 1: Run a Speed Test
Before troubleshooting anything, establish a baseline. Run the ExamineIP Speed Test and note your:
- Download speed (Mbps): How fast data comes to you
- Upload speed (Mbps): How fast you send data out
- Ping (ms): Latency to the test server
- Jitter (ms): Variation in ping — high jitter causes buffering and lag
Compare your results to what you pay for. If you’re getting dramatically less (under 50% of your plan speed consistently), proceed with diagnosis.
Step 2: Test Multiple Devices
Run the speed test on multiple devices — your laptop, phone, another computer. This tells you whether the problem is:
- Only on one device: The problem is that device (its Wi-Fi card, drivers, settings, or malware)
- On all devices: The problem is your router, modem, or ISP connection
Also test over ethernet (wired) vs Wi-Fi. If wired is fast but Wi-Fi is slow, the problem is your wireless setup, not your internet connection.
Step 3: Check Your Wi-Fi Signal
Wi-Fi speed drops dramatically with distance and through walls. Factors that hurt Wi-Fi performance:
- Distance from router
- Thick walls, floors, or metal objects between device and router
- Wi-Fi interference from neighbouring networks (especially on 2.4GHz)
- Router placement (don’t hide it in a cabinet or closet)
- Old Wi-Fi standard (Wi-Fi 4/802.11n is much slower than Wi-Fi 6/802.11ax)
Quick fixes: Move closer to the router, switch to 5GHz band (faster but shorter range), or change your Wi-Fi channel in the router settings to avoid interference.
Step 4: Restart Your Router and Modem
Before diving deeper: restart your router and modem. Unplug both from power for 30 seconds, then plug the modem in first, wait for it to connect, then plug in the router. This fixes a surprising number of performance issues caused by memory leaks, stale connections, or DHCP lease problems in the router’s software.
Step 5: Check for Bandwidth-Heavy Devices or Applications
Something on your network might be consuming all the available bandwidth:
- Windows Update running in the background
- A cloud backup service (Dropbox, OneDrive, iCloud) uploading large files
- A game downloading or updating
- Another household member streaming 4K video
- IoT devices or smart TVs running background updates
Check your router’s connected devices list and traffic stats. Many modern routers show per-device bandwidth usage.
Step 6: Check Your DNS Speed
DNS doesn’t affect download speed but it affects how quickly web pages start loading. Slow DNS resolution can make a fast internet connection feel sluggish because there’s a delay before each page begins loading.
Test your DNS with the DNS Checker. If your ISP’s DNS is slow, switch to Cloudflare (1.1.1.1) or Google (8.8.8.8) — both respond in under 5ms from most locations.
Step 7: Check for ISP Throttling
Many ISPs throttle specific types of traffic — video streaming, gaming, or P2P. They can identify traffic types even over HTTPS using deep packet inspection.
How to detect throttling:
- Run a speed test normally — note the result
- Connect to a VPN and run the speed test again
- If speeds are significantly higher with the VPN, your ISP is throttling your connection
A VPN encrypts your traffic, making it impossible for your ISP to identify and throttle specific types. PureVPN is a good option for bypassing throttling with fast server infrastructure.
Step 8: Check Your Modem’s Signal Levels
If you have cable internet, your modem maintains signal levels with your ISP’s network. Poor signal = poor performance. Log into your modem’s admin page (often at 192.168.100.1) and look for downstream and upstream signal power levels.
Normal levels vary by provider, but if your modem shows errors, uncorrectables, or signal levels far outside normal range, the problem is physical — cable quality, splitters, or the line from the street.
Step 9: Update or Replace Your Equipment
- Router firmware: outdated firmware has bugs and performance issues
- Router age: routers more than 5 years old may not support your plan’s full speed
- Modem compatibility: some ISP-provided modems cap speeds; check if your modem is on the ISP’s approved list for your tier
Step 10: Contact Your ISP
If all else fails and you’re consistently getting far below your subscribed speed, contact your ISP with documented evidence (speed test screenshots taken at different times of day). Most ISPs will send a technician to check the line if you can demonstrate the issue persists.
Quick diagnosis summary: Single device slow = device problem. All devices slow on Wi-Fi but fast on ethernet = Wi-Fi problem. All devices slow on both = router/modem/ISP problem. Specific services slow = possible throttling (test with VPN).