First, separate the line from the Wi-Fi
Most "slow internet" is actually slow Wi-Fi, and the two need very different fixes. Before you blame your provider, you have to know which side of the router the problem lives on. The cleanest way is to plug a laptop directly into the router with an Ethernet cable and run a speed test. If the wired result matches your plan but Wi-Fi is far slower, the line is fine — your wireless coverage is the bottleneck. If even the wired test is slow, the problem is the router, the modem or the line itself.
No cable handy? Stand next to the router with one device and test, then test again from the room where it feels slow. A big drop between the two locations is a coverage problem, not a provider problem.
The diagnostic checklist, in order
Do these in sequence and re-test after each one. Stopping the moment speeds recover tells you exactly what the cause was.
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1. Reboot the modem and router
Power both off for a full two minutes, then on. This clears full memory, drops stale sessions and lets the modem re-sync the line. It is the highest-value free step — re-test before doing anything else.
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2. Test wired vs wireless
As above: a wired test isolates the line from your Wi-Fi. This one check splits every "slow internet" problem into two completely different troubleshooting paths.
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3. Count what's using the connection
A background console update, a cloud backup or someone streaming 4K can eat your whole line. Pause big transfers, then re-test. If speed jumps back, you found a bandwidth-hog, not a fault.
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4. Check latency, not just Mbps
Run a ping test and a bufferbloat test. If Mbps is fine but ping is high or spikes under load, that — not speed — is why everything feels sluggish.
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5. Move or declutter the Wi-Fi
Lift the router off the floor, away from walls and metal, and switch crowded devices to the 5 GHz band. Channel overlap with neighbours is a silent speed killer in flats.
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6. Compare against your plan
Three wired tests, at different times, averaged. Consistently far below what you pay for — with the rest ruled out — is when it's time to gather proof and call the ISP.
What the numbers actually mean
A speed test gives you more than one figure, and "slow" can hide in any of them. Here is how to read a result and decide whether it's genuinely a problem.
| Metric | What it controls | Healthy range |
|---|---|---|
| Download | Streaming, browsing, downloads | 50–300+ Mbps |
| Upload | Video calls, cloud, sharing | 10–50+ Mbps |
| Ping | Responsiveness, gaming, calls | < 50 ms |
| Jitter | Call/voice stability | < 10 ms |
| Packet loss | Dropouts, stutter, lag | 0% |
The trap most people fall into: chasing a bigger download number when their real problem is in the bottom three rows. A line with 500 Mbps down but 120 ms ping under load will feel worse for calls and games than a 50 Mbps line with rock-steady latency. For a deeper breakdown, see our guide to lowering your ping.
The five most common culprits
In practice, almost every "why is my internet slow" case lands on one of these. Knowing the symptom shortcut saves a lot of guesswork.
1. Weak or crowded Wi-Fi
Distance, walls and neighbouring networks all sap wireless speed. The tell-tale sign is a fast wired test and a slow wireless one, getting worse the further you move from the router. Fixes: relocate the router, switch to 5 GHz, pick a clearer channel, or add a mesh node for dead zones.
2. An overloaded or ageing router
Cheap or old routers choke when many devices connect at once, and their buffers cause latency spikes under load. If a reboot fixes things temporarily and a wired test is still soft, the router is the weak link.
3. Bandwidth being eaten elsewhere
Automatic updates, cloud sync, torrents and 4K streams quietly consume the whole pipe. This is the most common false alarm — pause the big transfers and the "fault" disappears.
4. Latency, jitter and bufferbloat
When speed looks fine but the experience is awful, the problem is how late packets arrive, not how many. Bufferbloat — latency that balloons the instant the line gets busy — is the classic culprit, and it's fixable with Smart Queue Management (SQM) on a capable router. Confirm it with the bufferbloat test.
5. A real ISP or line fault
Only after the above: degraded copper, a failing modem, an oversubscribed local node, or throttling. These show up as consistently low wired speeds, packet loss, or evening-only slowdowns. That's your cue to escalate — with data.
Is it your ISP? How to gather proof
Support lines move fast when you bring evidence instead of frustration. Before you call, collect:
- Three or more wired speed tests at different times of day, with timestamps and the server used.
- A packet loss or stability check showing dropouts on the line, not just your Wi-Fi.
- Your plan's advertised speed next to your measured average, so the gap is undeniable.
- Modem signal levels if you can reach the admin page — poor levels point to a physical line fault.
With that in hand, ask them to log a fault and check line sync and the local node. If they confirm everything is healthy on their side, the evidence points back inside your home — and the checklist above is where the fix lives.
Skip the guesswork — run a full diagnosis
The Doctor runs the whole panel — download, upload, ping, jitter, packet loss and bufferbloat — then reads the results together and tells you the most likely cause and exactly what to fix first. It's the checklist above, automated.
Frequently asked questions
- Why is my internet slow at night but fine during the day?
- Evening slowdowns usually point to congestion — either your local neighbourhood node is saturated during peak hours, or your own household is using more bandwidth (streaming, downloads, updates) than you realise. Run a speed test at 9pm and again at 7am: a large gap that only appears in the evening, on a wired connection, is a strong sign of ISP or node congestion rather than a fault in your home.
- My speed test looks fine but everything still feels slow. Why?
- Throughput (Mbps) is only one of three vital signs. If download and upload look healthy but pages, calls and games still stutter, the problem is almost always latency — high ping, jitter or bufferbloat. A connection can be 'fast' on paper and still feel broken because packets are arriving late or out of order.
- Does restarting my router actually help?
- Often, yes. A reboot clears a full memory, drops stale connections, lets the modem renegotiate a clean line sync, and can move your Wi-Fi to a less crowded channel on boot. It is the single highest-value free step, which is why it sits near the top of the checklist — just give it a full two minutes before powering back on.
- How fast does my internet need to be?
- For one person browsing and doing HD video calls, 25–50 Mbps down and 5–10 Mbps up is plenty. A busy household with 4K streaming and several devices is comfortable at 100–300 Mbps. Beyond that, more raw speed rarely fixes 'slow' — stable latency matters far more than headline Mbps.
- When should I just call my ISP?
- Call once you have evidence: repeated wired speed tests well below your plan, packet loss on the line, or a modem showing poor signal levels. Walking in with timestamps and numbers gets a fault logged far faster than 'the internet feels slow'.