Internet Speed Test Glossary
Confused by the numbers on your speed test? Here's what every metric means, explained in plain English.
Download Speed (Mbps)
How fast data travels from the internet to your device. This is the number ISPs advertise (e.g., "300 Mbps plan"). It affects streaming, loading web pages, and downloading files.
Real-world example: At 100 Mbps, you can download a 5 GB movie in about 7 minutes. At 10 Mbps, it takes over an hour.
Upload Speed (Mbps)
How fast data travels from your device to the internet. This matters for video calls, live streaming, cloud backups, and sending large files.
Why it's usually slower: Most home connections (cable, DSL) are asymmetric — they prioritize download because most users consume more than they create. Fiber plans often offer symmetric speeds (e.g., 300 down / 300 up).
Ping (Latency)
The time it takes for a small data packet to travel from your device to a server and back, measured in milliseconds (ms). Lower is better.
Benchmarks:
- 0-20 ms: Excellent (fiber, wired)
- 20-50 ms: Good (most broadband)
- 50-100 ms: Acceptable (Wi-Fi, 4G)
- 100-200 ms: Noticeable lag in games
- 200+ ms: Poor (satellite, congested networks)
Jitter
The variation in ping over time. If your ping is 20ms one moment and 80ms the next, you have high jitter. It causes choppy audio and frozen video in calls.
Good jitter: Below 10ms. Bad jitter: Above 30ms. High jitter usually indicates Wi-Fi interference, network congestion, or a struggling router.
Packet Loss (%)
The percentage of data packets that never reach their destination. Even 1-2% packet loss can cause visible issues in games and video calls.
Causes: Faulty cables, overloaded routers, Wi-Fi interference, or ISP infrastructure problems. 0% is ideal; anything above 2% is problematic.
Bandwidth vs. Speed
Bandwidth is the maximum capacity of your connection (like the width of a highway). Speed is how fast data actually moves (like the speed limit). You can have 500 Mbps bandwidth but only get 200 Mbps speed if the network is congested.
Mbps vs. MB/s
Mbps = Megabits per second (used by ISPs). MB/s = Megabytes per second (used by file downloads). 1 Byte = 8 bits. So 100 Mbps ≈ 12.5 MB/s actual download speed.
This is why your "100 Mbps" plan shows ~12 MB/s when downloading a file from Steam. You're not being cheated — it's just a different unit.