In simple terms
Bandwidth is the carrying capacity of a connection: how much data it can move in a second. It is usually written in megabits per second, or Mbps.
Picture a pipe. Bandwidth is how wide the pipe is, not how fast any single drop travels down it.
How it works
Download and upload capacity are measured separately, because most home lines give far more of one than the other. Regulators set both numbers. Since 14 March 2024 the US Federal Communications Commission counts a fixed service as broadband only at 100 Mbps down and 20 Mbps up, raised from the 25 and 3 set in 2015, with a long term goal of 1 Gbps and 500 Mbps.
Those thresholds are national. A connection advertised as broadband in one country may fall below the line in another.
The advertised figure is also shared. It describes what the line can carry in total, split between everyone and every device using it at that moment.
Capacity is not the whole story either. Ofcom, measuring UK mobile networks from October 2024 to March 2025, found a 2 MB file took about 0.3 seconds to arrive on 5G, 0.7 seconds on 4G and 4.9 seconds on 3G, and reported latency separately, because response time is a different quantity.
Why it matters
Video calls, streaming, cloud backups and software updates all draw on the same capacity at the same time, and the ceiling is fixed.
Governments use bandwidth thresholds to decide which areas count as underserved, which in turn decides where public subsidy goes.
More bandwidth does not fix everything. A high capacity line with poor latency still feels sluggish on a call or in a game.
Where you’ll see it
- Broadband and mobile plans advertised by speed.
- Speed test results showing separate download and upload figures.
- Router, Wi-Fi and data center equipment specifications.
- National broadband coverage and connectivity reports.
Example
A household on a 100 Mbps line streams two high resolution videos, uploads a photo backup and holds a video call at once. Each one slows, not because the line changed, but because they are dividing one fixed capacity.
Often confused with
Engineers also use bandwidth to mean the width of a band of frequencies, measured in hertz. The two are related, since more spectrum generally allows a higher data rate, but they are not the same quantity. Bandwidth is also distinct from latency, which is the delay before data starts arriving at all.
Key facts
- Since 14 March 2024 the US fixed broadband benchmark has been 100 megabits per second download and 20 Mbps upload.1
- The previous US benchmark, set in 2015, was 25 Mbps download and 3 Mbps upload.1
- The FCC also set a long term goal of 1 gigabit per second download and 500 Mbps upload.1
- Ofcom measurements from October 2024 to March 2025 found a 2 MB file took about 0.3 seconds to download on 5G, 0.7 seconds on 4G and 4.9 seconds on 3G.2
- Ofcom reports latency, or average response time, separately from download speed, and found standalone 5G both faster and lower latency than non-standalone 5G.2
Related concepts
In the news
Quick checkWhat is the difference between bandwidth and latency?Show answer
Bandwidth is how much data a connection can carry per second. Latency is the delay before data starts arriving. A line can have plenty of one and still be poor at the other.
Sources
- Federal Communications Commission. FCC increases broadband speed benchmark. 14 March 2024 (accessed 18 September 2026)
- Ofcom. Mobile Matters: download speeds, connection rates and latency levels revealed. 17 July 2025 (accessed 18 September 2026)
Editorially reviewed by Specialty Digest Editorial TeamLast reviewed September 21, 2026Researched and drafted with AI assistanceReport an issue