Running a single speed test and reading the big number off the screen tells you surprisingly little about your connection. That figure blends your Wi-Fi, the device, the time of day and the route to a distant server into one summary that hides more than it reveals. A proper test isolates those variables one at a time, so you learn whether a problem sits in your line, your wireless, or somewhere out on the wider internet. This walkthrough shows how to measure what genuinely matters, latency and jitter included, and how to make sense of the numbers once you have them.
Start with a wired test
The first job is to remove Wi-Fi from the picture entirely. Plug a laptop directly into the router with an Ethernet cable and run the test again. If the wired figure matches your plan but wireless falls short, the fault is in the local Wi-Fi, not the line your provider delivers. A wireless result is always capped by the Wi-Fi version your laptop and router negotiate, so the primer on what separates the Wi-Fi standards is worth a look before you blame the connection itself.
Use a cable you trust and a port on the router itself rather than a switch or wall socket further down the chain. An old or damaged Ethernet lead can quietly limit a gigabit line to a fraction of its speed and send you chasing a fault that is not really there. Once the wired reading is stable and repeatable, you have a solid reference point that everything else in the testing can be measured against.
Then measure over Wi-Fi
With a wired baseline recorded, repeat the test from the spots where you actually use your devices. A large gap between the wired and wireless numbers, especially one that grows as you move away from the router, points to coverage or interference rather than the provider. Cordless phones, baby monitors, neighbouring networks and even a microwave can all eat into the signal, the sort of causes catalogued in the guide to sources of wireless interference at home. Testing room by room turns a vague complaint into a clear map of where the trouble lives.
Time of day and congestion
A connection is not a fixed thing across the day. On shared technologies like cable, the speed you get at ten in the morning can differ sharply from what you get at nine in the evening, when the whole street is streaming at once. A single test at a quiet moment can look perfect while the connection struggles every night. Measuring at both peak and off-peak times, and writing down each result, reveals whether contention is the real issue rather than a fault on your own equipment.
The shape of the pattern is itself informative. A connection that holds its speed through the evening rules out local contention, while one that collapses only at peak hours points to a shared segment carrying too many neighbours at once. Noting the clock beside each result, instead of treating every test as interchangeable, is often what separates a genuine provider problem from a fault sitting inside your own four walls.
A procedure you can repeat
Consistency is what makes results comparable, so run the same sequence each time you test.
- Close background apps and pause any cloud sync or downloads that could quietly skew the figures.
- Connect a computer to the router by Ethernet and let the link settle for a moment before starting.
- Choose a test server near you to measure the line, then note the download, upload, ping and jitter.
- Run the test three times and take the middle result rather than the single best one.
- Repeat over Wi-Fi from your usual spots, recording the same four numbers for each location.
- Test once at a quiet hour and once at the evening peak, then compare the two sets side by side.
Latency and jitter, not just megabits
Speed in megabits is only part of the story. Ping, or latency, is the delay before data starts to move, and jitter is how much that delay wobbles from one moment to the next. For video calls, gaming and even ordinary browsing, low and steady latency matters more than a huge download figure. A line that tests at 500 megabits but spikes in latency under load will feel worse than a slower, calmer one. What these numbers mean, and why they behave as they do, is set out in the explainer on what latency actually measures.
Choosing a server and reading the numbers
Which server you test against changes what you are really measuring. A server hosted by your own provider, or one physically near you, gauges the health of your line. A distant server instead measures the longer path across the internet, which answers a different question. For judging what you pay for, pick the nearest neutral server and test against that.
Reading the results means comparing them against your plan sensibly. Advertised speeds are an upper limit, and normal overhead means you will see a little less than the rated figure even on a healthy line. If throughput is far below the plan, or latency climbs sharply the moment traffic flows, something is genuinely wrong. Remember too that other devices, and any filtering appliance on the network, can drag a test down, a point covered in the guide to filtering traffic on a home network.
What this means in practice
A meaningful test is less about the single largest number and more about a set of readings taken under controlled conditions. Wired first, then wireless, at different times, watching latency and jitter as closely as raw speed, gives you evidence rather than a hunch. That evidence is what turns a call to your provider from a vague grumble into a specific, answerable question about your service.
Keep a short record of your results over a week or two. Patterns emerge that a one-off test simply cannot show, whether an evening slowdown, a particular room that lags, or a steady gap between what you pay for and what arrives. With that record in hand, you can tell whether the fix lies inside your home or with the line itself.
Frequently asked questions
Why is my speed test lower than my plan?
Several things pull a test below the advertised figure. Testing over Wi-Fi rather than a cable, running it at a busy evening hour, choosing a distant server, or having other devices active all lower the result. Advertised speeds are also an upper limit, so a small shortfall is normal. Test wired, at a quiet time, against a nearby server before concluding that your line is underperforming.
How do I test my real internet speed?
Connect a computer to the router with an Ethernet cable, close background apps and cloud sync, then run a reputable speed test against a nearby server three times and take the middle result. Record download, upload, ping and jitter each time. Repeat over Wi-Fi and at different times of day. This sequence separates your line, your wireless and network congestion instead of blending them into one figure.
What is a good ping and jitter?
On a fixed home connection, a ping under about 20 milliseconds to a nearby server is very good, and under 40 is fine for most uses. Fibre often sits in single digits, while DSL runs higher. Jitter, the variation in that delay, should ideally stay under 5 milliseconds. Low, steady figures matter most for calls and gaming, where spikes cause the stutters and dropouts you notice.
