Terabit per second to Kilobyte per second

Global internet traffic peaks at roughly 1,000–1,500 Tbps (1–1.5 Pbps) as of 2026. This is growing at about 25% per year, driven by video streaming, cloud computing, and AI training data transfers. A single viral live event can spike regional traffic by tens of Tbps.

Internet traffic automatically reroutes through other cables and paths via BGP routing protocols, usually within seconds. Speed may degrade in the affected region but rarely drops entirely. Cable cuts happen more often than people think — about 100 per year globally, mostly from ship anchors and fishing trawlers.

Dense wavelength-division multiplexing (DWDM) sends dozens of different light colors (wavelengths) through a single fiber simultaneously, each carrying its own data stream. A modern cable contains multiple fiber pairs, each carrying 100+ wavelengths, with each wavelength modulated at 400 Gbps or more.

Netflix's library is estimated at around 30–40 petabytes. At 1 Tbps, downloading the entire catalog would take roughly 70–90 hours. At 100 Tbps (a realistic submarine cable capacity), you could theoretically grab all of Netflix in under an hour.

Researchers at Japan's NICT achieved 22.9 Pbps (22,900 Tbps) through a single multicore fiber in 2024. That is enough to transfer the entire Library of Congress in a fraction of a second. These lab records typically reach commercial deployment 5–10 years later.

A typical 4 MB MP3 file at 7 kB/s took about 9–10 minutes to download. Napster users in 1999 would queue up songs before bed and hope the phone line stayed connected overnight. A single disconnection meant starting over from scratch.

Lowercase "k" with uppercase "B" (kB/s) means 1,000 bytes per second (SI decimal). Uppercase "K" with uppercase "B" (KB/s) traditionally meant 1,024 bytes per second (binary). In practice, most software uses them interchangeably, and the difference is only 2.4%.

Apps display kB/s when transfer speeds are genuinely that slow — downloading over congested mobile networks, tethering in rural areas, or transferring tiny files where the connection never ramps up. It is also common in SSH/SCP transfers that display instantaneous speed during small file copies.

The first consumer ADSL plans offered 256 kbps downstream, delivering about 32 kB/s — roughly 4.5× faster than a 56k modem. A 512 kbps plan gave 64 kB/s. That first jump from 7 to 32 kB/s felt revolutionary, cutting a 10-minute download to about 2 minutes.

An SMS is limited to 140 bytes (160 characters in GSM-7 encoding), and the signalling channel transmits it almost instantly. But if you think of SMS throughput over a sustained period, the practical rate is about 0.1–0.5 kB/s because of the overhead between messages.