25-50 Mbps is enough for one person browsing and watching HD video. Allow about 100 Mbps for one or two people with a 4K TV, 200-300 Mbps for a family of three or four with 4K and video calls, and 500 Mbps to 1 Gbps for five or more people with several 4K streams and gaming.
Upload matters separately: 5 Mbps for light use, 10 Mbps for regular video calls, and 35-50 Mbps for cloud backups or live streaming. Add roughly 25% headroom on top of everything running at once, then use the calculator below for your exact mix.
Pick how many of each activity will run at the same time on your network. We add 25% headroom because real-world TCP overhead, retransmissions, and background updates always eat more than the spec sheet suggests.
These are practical targets for everything running at the same time, including the 25% headroom explained below.
Before paying for a faster plan, run a speed test and compare your measured download speed with what you already pay for. If the gap is large, the limit is usually WiFi or the router rather than the plan, and the slow internet guide is the cheaper fix.
Each activity has a typical sustained bitrate. Streaming a single 4K Netflix title averages around 25 Mbps. Two 4K TVs plus a Zoom call already passes 50 Mbps, and that's before background traffic from phones, smart speakers, and OS updates.
TCP doesn't run at line rate continuously, overhead, retransmissions, and the bursty nature of HTTP/2 mean you need ~20-30% more headroom than the raw codec bitrate suggests. Without headroom, video re-buffers when a phone in the background decides to download an app update.
Most ISP plans advertise download speed. Cable and DSL plans often have upload speeds that are 5-10× lower. If you're a streamer, work-from-home worker, or back up to the cloud, look at the upload number too.