What is the difference between bandwidth and download speed?

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What is the difference between bandwidth and download speed?

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Speed is like the speed you drive in your car. Bandwidth is like the gas in the tank. In very basic terms.

bandwidth is how much data can go through the pipe the way you’re trying to use it.

trying to upload? your uploadspeed is your bandwidth

trying to download from a source providing the data at high enough speeds? your downloadspeed is your bandwidth

trying to download a huge file from your friends private homepage he’s hosting on his old laptop in his room? your downloadspeed is lower than your actual bandwidth (because it’s limited by his upload-bandwidth).

From what I understand, bandwidth is about load, speed is about speed. So you may have the bandwidth to support 3 devices all streaming at the same time, any more than that impacts performance. But your neighbour might have the bandwith to support 5 devices all streaming at the same time before any impact, however both houses can download at 25mb/sec

The bandwidth is the maximum amount of data that can travel over the connection. This will normally be constant but for some connection types can vary. It an also sometimes be shared e.g. your internet bandwidth is shared between all the things in your house that want to talk to the outside world.

The download speed is how fast a file is arriving at your computer. This will always be less than the bandwidth due to overheads (see below) but could be significantly lower since it will be limited by the slowest part of the connection between you and the place you are downloading from.

Overhead is all the other stuff going on over a network connection that you don’t care about, a lot of it is invisible to the user. During a download there will requests for the next block, acknowledgements that messages have arrived etc… There will normally also be a small amount of housekeeping data maintaining the link. Wireless links often have a lot more overhead since they require more constant status checking than a wire.
While this is generally a small amount of data it does reduce the maximum rate available for the actual thing you are downloading.

And there will be gaps in data while the computer at the other end works out what to send next. Although these aren’t technically overhead the need for some processing time means it’s rare to hit 100% on a link for long periods.

Edit-just to note in advertising the two will often be used interchangeably, maximum download speed and bandwidth are normally close enough to not make much difference.

If download speed is like the speed limit on the road, bandwidth is how many lanes there are on the road. A 100 lane road with a speed limit of 1 mph can transfer the same amount of cars (data) as a 1 lane road with a speed limit of 100 mph.

Bandwidth is like a water pipe that you can receive and push water through at the same time. Download speed is the amount of water you are receiving through the pipe. You can not get more water through the pipe than the diameter of the pipe. (can’t have higher download speed than your bandwidth). If you uploading and downloading, it going to have to share the ‘space in the pipe’.

You are connected to other people’s pipes, if you trying to water from Bob but he has a small pipe, you will only get at maximum the amount of water he pipe can provide no matter how much space your pipe has.

If you want more bandwidth you’ll have to pay for a bigger pipe. But it will not improve download speed if it being limited by ‘Bob’s’ pipe.

Bandwidth is the size of your pipe.

Download speed is how much water actually flows through it.

You can build an house with a 10″ diameter pipe, which would allow you to have tons of water, but then the water provider only sends you 2″ worth of water through it.

In terms of internet connection, the bandwidth is given by the physical infrastructure, which means the actual cables in the streets and your house. The download speed is dictated by the provider and your contract.

bandwidth – the diameter of the pipe

download speed – how much water is actually running through

There are a lot of good answers here but we’re missing the key terminology, which is [bandwith versus throughput](https://www.indeed.com/career-advice/career-development/throughput-vs-bandwidth).

They are ways of describing the digital and analog nature of a network connection.

Bandwidth is often misused in relation to data rate (speed). There is no direct relationship between the bandwith being used and the data rate, though there are maximum practical limits on how much data you can fit within a set band.

Bandwidth(analog) is measured in Hertz(cycles per second), and is the range of the frequency spectrum the signal occupies.

Data Rate(digital) is measured in Bps(bits per second), all the ones and zeros passing through in a second

Your internet connection which is comprised of binary data from the websites/emails you are working with on your computer with additional data wrapped around it for routing/encryption etc. That is then converted from digital(binary) data into an analog signal do be transmitted from your network to your ISP then on to the destination. This occurs at the modem(Modulator/Demodulator) for cable internet or the ONT(Optical Network Terminal) for fiber based connections or the transceiver for a WiFi link (copper/fiber/radio is the transmission medium).

For example a standard FM radio signal has a data rate of 64KBps but a bandwidth of 267kHz

Bandwidth is the size of the pipe. Bigger the pipe higher the bandwidth.

It’s the difference between a two lane highway and a four lane highway.

Speed is how fast the cars and go on the highway.

If the bandwidth is low (two lanes) it doesn’t matter if the cars in back can go 80 MPH when the cars in front of them are only going 30 MPH.

If the bandwidth is higher (four lanes) then those cars can go 80 MPH because there’s nothing causing congestion.

Bandwidth is one of those words that somehow got several different meanings. It usually means the speed you can upload or download at. It can also mean the total amount you’re allowed to upload or download in a month. It can also mean a different thing when talking about radio waves.