Broadband packages are sold on a single headline number: download speed in Mbps. But that number tells you less than you might think, and the metrics that matter most for your actual experience are rarely the ones ISPs advertise.
Download speed
This is the number your ISP puts on the tin. It measures how fast data can travel from the internet to your device — how quickly you can load a webpage, stream a video, or download a file.
For most households, a download speed of 30–50 Mbps is comfortably enough for streaming 4K video, video calls, and general browsing simultaneously across multiple devices. The headline numbers ISPs compete on — 100 Mbps, 500 Mbps, 1 Gbps — matter mainly if you’re regularly transferring large files or have many people doing bandwidth-intensive things at once.
When it matters most: Downloading large files, streaming video, loading pages.
Upload speed
Upload is how fast data travels from your device to the internet. Historically ISPs have under-provisioned this compared to download, because most consumer usage was asymmetric — you watch far more than you broadcast.
That’s changed. Video calls, cloud backups, working from home, gaming, and social media all put significant load on upload speed. A package with 80 Mbps download but 5 Mbps upload can feel slow in a way that the download number doesn’t predict.
When it matters most: Video calls, working from home, cloud backups, live streaming.
Latency
Latency is the time it takes for a signal to travel from your device to a server and back — usually measured in milliseconds (ms). It’s also called ping.
Low latency doesn’t make your download faster, but it makes everything feel more responsive. Web pages load sooner (even if the total data is the same). Video calls feel natural rather than laggy. Online games are playable rather than frustrating.
A latency of under 20ms is excellent. 20–50ms is good. 50–100ms is acceptable for most things. Over 100ms and you’ll start to notice lag on video calls and gaming.
When it matters most: Gaming, video calls, general responsiveness and “snappiness.”
Packet loss
Packet loss is the percentage of data packets that don’t arrive at their destination. At 0%, everything is fine. Even at 1–2%, you’ll notice problems — choppy video calls, stuttering games, unreliable connections.
Packet loss is often the hidden cause of a connection that “feels” slow or unreliable even when a speed test looks fine. It’s much rarer than latency issues, but harder to self-diagnose without monitoring tools.
When it matters most: Video calls, gaming, real-time applications.
Jitter
Jitter is the variation in latency over time. If your latency averages 15ms but swings between 5ms and 80ms, that variation — the jitter — causes problems for real-time applications even if the average looks okay.
High jitter is often a sign of network congestion — either on your home network or your ISP’s.
When it matters most: Video calls, gaming, VoIP.
Which numbers should you actually care about?
For most people, in rough order of importance:
- Latency — the biggest determinant of how “fast” your connection feels day-to-day
- Packet loss — even small amounts cause disproportionate problems
- Download speed — important, but often overstated; 50 Mbps does most things
- Upload speed — increasingly important if you work from home or video call regularly
- Jitter — matters for gaming and calls, less so for general browsing
The trap most people fall into is chasing a higher download number when their actual problems are caused by latency or packet loss — metrics that a faster package won’t fix.
How to know if your numbers are good
Run a speed test — but do it at different times of day, especially during peak evening hours (7–10pm). A connection that delivers 80 Mbps at 11am but 12 Mbps at 8pm is a congestion problem, not a line problem, and switching to a faster package from the same ISP won’t help.
Better still, monitor continuously. A single speed test is a snapshot. A month of data is a pattern — and patterns are what you need to understand whether your connection is genuinely underperforming, at what times, and whether the problem is getting worse.