Symptoms
- Speed test results are noticeably below your plan's advertised speed
- Slowness happens on all devices, not just one
- Speeds were fine before and have gradually or suddenly dropped
- Wired and wireless speed tests give very different results
Likely causes
- CommonTesting over Wi-Fi instead of a wired connectionWi-Fi speeds are almost always lower than the wired maximum due to signal, distance, and interference, so this alone can explain a big gap.
- CommonRouter hardware can't handle the full speed of your planOlder routers may cap out well below what a newer, faster internet plan can deliver.
- PossibleMultiple devices using bandwidth during the testBackground downloads, streaming, or cloud backups elsewhere in the house reduce available speed for your test.
- PossibleProvider-side congestion or a line issueOccasionally the fault is genuinely on the provider's network or the physical line into your home.
What to do
- Run a speed test using a device connected directly to the modem or router via Ethernet cable, not Wi-Fi, for the most accurate baseline.
- Run the test at different times of day, since evening peak hours can show lower speeds even with a perfectly fine connection.
- Pause all other downloads, streaming, and updates on every device in the house during the test.
- Restart the modem and router, then retest.
- Check your router's specifications to confirm it's rated to handle your plan's speed; an older router may cap speeds well below a newer high-speed plan.
- Test with multiple speed test services (not just one) since results can vary slightly by server location.
- If a wired test consistently shows speeds well below your paid plan after ruling out router limitations, contact your ISP; they can check the line and may need to send a technician or replace equipment.
Tools and parts
- Ethernet cable
- Speed test website or app
When to call a pro
If a wired speed test consistently underperforms your plan after ruling out your own equipment, your ISP should investigate the line and may credit your account for the shortfall.
Safety
Generally low risk for a careful person. Stop if anything looks different from what this guide describes.