Why are internet upload speeds so much slower than download speeds?

Most home internet users get much slower upload speeds than download speeds because they typically consume far more data than they send, and providers allocate capacity accordingly. The difference also reflects technical limits in cable networks, while fibre connections can generally support equal speeds in both directions.

Cable internet uses shared copper lines originally designed mainly to deliver television, so providers divide their limited capacity between uploads and downloads, favouring downloads. Newer DOCSIS standards can improve speeds, but require investment in equipment; cable performance may also dip when neighbours are online. Fibre carries data using light and has much greater capacity, avoiding many of these constraints. Content delivery networks also help companies place copies of data closer to users, making downloads more efficient.