Ever run a speed test and wondered what all those numbers actually mean?
This guide explains common internet speed terms in plain English so you can better understand your connection and know what to expect from your service.
What Is a Speed Test?
A speed test measures how your internet connection is performing at that moment.
It checks:
- Download speed
- Upload speed
- Ping (latency)
- Jitter (connection consistency)
A speed test can help you understand whether slow browsing, buffering, lag, or poor video calls may be related to your connection.
Before You Run a Speed Test
For the most accurate results:
- Use a network cable (Ethernet) instead of wifi
- Pause downloads, streaming, gaming, and cloud backups
- Disconnect unnecessary devices from your network
- Run multiple tests at different times of day
- Test from the same device
Testing over wifi can give lower or inconsistent results due to walls, interference, distance, or device limitations.
If you are testing wifi performance, make sure you are close to the router or mesh device.
How to Run a Speed Test
You can run a speed test using a trusted testing platform such as Speedtest.net.
For the best consistency:
- Connect directly to your router using a network cable
- Close apps using the internet
- Run the test two or three times
- Compare the average result to your package speed
Your result may vary depending on:
- Wifi signal quality
- Network congestion
- Device age and capability
- Time of day
- Server location
Download Speed
Download speed is how quickly data moves from the internet to your device.
This affects:
- Streaming video
- Loading websites
- Downloading files
- Online gaming downloads
- App updates
Example:
If Netflix buffers or websites load slowly, download speed may be the cause.
Higher download speeds generally mean faster loading and smoother streaming.
Upload Speed
Upload speed is how quickly data moves from your device to the internet.
This affects:
- Video calls
- Uploading photos and videos
- Cloud backups
- Sending large files
- Live streaming
Example:
If your video freezes during a Teams or Zoom meeting, or files take ages to upload, your upload speed may be low.
Ping (Latency)
Ping, also called latency, measures how quickly your device communicates with a server and gets a response back.
It is measured in milliseconds (ms).
Lower is better.
Typical examples:
- 0 to 20ms → Excellent
- 20 to 50ms → Very good
- 50 to 100ms → Good
- 100ms+ → Noticeable delay
Latency matters most for:
- Online gaming
- Voice calls
- Video calls
- Real-time applications
High latency may feel like lag, delay, or slow responsiveness.
Jitter
Jitter measures how stable your connection is.
In simple terms, it shows whether your latency stays consistent or jumps around.
Low jitter = smoother experience
High jitter may cause:
- Choppy voice calls
- Frozen video meetings
- Gaming lag spikes
- Interrupted streaming
Even if your speed is high, poor stability can still create a bad experience.
Mbps vs MB/s
This one catches a lot of people out.
Mbps (Megabits per second) measures internet speed.
MB/s (Megabytes per second) measures file download speed.
There are 8 bits in 1 byte.
Example:
A 100Mbps fibre package will usually download files at around 12.5MB/s under ideal conditions.
So if Steam, Xbox, PlayStation, or Windows shows 12MB/s, that is actually normal for a 100Mbps connection.
Why Am I Not Getting Full Speed?
It is normal to sometimes see speeds lower than your package speed.
Wifi Limitations
Distance, walls, interference, and older devices can reduce speeds.
Older Devices
Older phones, laptops, TVs, or routers may not support higher speeds.
Multiple Connected Devices
Streaming, gaming, downloads, and smart devices all share bandwidth.
Busy Periods
Internet usage can fluctuate depending on demand and the destination server.
Testing Server Location
A server further away may show slower results or higher latency.
Fibre Speed vs Wifi Speed
Your fibre speed and wifi speed are not always the same thing.
Think of it like this:
Fibre speed = the speed entering your home
Wifi speed = how efficiently your device receives that connection
A wired test may show full speed while wifi appears slower. This is normal and usually related to signal strength, interference, or device capability.
For the best speeds:
- Stay close to the router or mesh unit
- Use the 5GHz wifi band when nearby
- Reduce interference from thick walls or appliances
- Use a wired connection for testing
Quick Glossary
| Term | Meaning |
|---|---|
| Download Speed | Speed from internet to your device |
| Upload Speed | Speed from your device to the internet |
| Ping / Latency | Response time between device and server |
| Jitter | Stability of the connection |
| Mbps | Internet speed measurement |
| MB/s | File transfer speed |
Key Takeaway
A speed test is more than just one number.
Good internet performance depends on:
- Speed
- Stability
- Low latency
- Strong wifi coverage
- Device capability
For the most accurate result, always test using a network cable first and compare that result to wifi performance.