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Download speed calculator

Calculating download times can be confusing if you don't know your bits from your bytes. Our download calculator can help you figure out how long it'll take you to download popular file sizes.

Although they sound the same, bits and bytes are different from one another. Both refer to an amount of information or data, but they're different sizes. A bit (represented by a lowercase 'b') is a binary digit 1 or 0, and a byte (represented by an uppercase 'B') is eight of these. This means a kilobyte (Kb) is eight times larger than a kilobit (kb), and a megabyte (MB) is eight times larger than a megabit (Mb).

Part of the reason for the confusion is that files sizes are usually displayed in bytes, but internet speeds are always shown in bits.

We've simplified things with our download speed calculator, which will show you the actual time to download different file types.

Download calculator

Below is a table full of theoretical speeds. The file size is written in megabytes (multiply by eight to get megabits) and the speeds are in megabits (divide by eight to get megabytes).

Four, eight, 16, 32, 50, and 100 represent some of the most common speeds in broadband, whether it's ADSL, 4G or cable. The table below will tell you approximately how long, in minutes and seconds, the file types on the left will take to download using the speeds on the right.

Keep in mind when you read the table that actual speed is rarely as fast as advertised or 'up to' speed, and there are many additional factors that affect speed. Realistically, the times below should be multiplied by four or five to get a more accurate figure from our download estimator.

Download speed calculator

ITEM Size (MB) 4Mbps 8Mbps 16Mbps 32Mbps 50Mbps 100Mbps
Single song 5 10s 5s 2.5s 1.25s 0.8s 0.4s
YouTube clip (LQ) 10 20s 10s 5s 2.5s 1.6s 0.8s
YouTube clip (HQ) 50 1m 40s 50s 25s 12.5s 8s 4s
Album (HQ) 100 3m 20s 1m 40s 50s 25s 16s 8s
TV Show (HQ) 450 15m 7m 30s 3m 45s 1m 52s 1m 12s 36s
Film (LQ) 700 23m 20s 11m 40s 5m 50s 2m 55s 1m 52s 56s
Film (HQ) 1500 50m 25m 30s 12m 30s 6m 15s 4m 2m
Film (full DVD) 4500 2h 30m 1h 15m 37m 30s 18m 45s 9m 22s 4m 41s
Film (BluRay) 10,000 5h 35m 2h 47m 1h 24m 42m 26m 40s 13m 20s

Mbs and MBs

Megabits are written Mb, and megabytes are written as MB. All internet speeds are measured in bits per second. An 'up to 8Mbps' connection means the maximum you will get is eight megabits per second, or the equivalent of one megabyte per second.

Doing the maths, this means if a provider or salesperson tries to tell you that an 8Mbps internet connection is equal to eight megabytes per second, they are wrong to a factor of eight.

Sometimes they'll try to get around this by simply referring to 'megs', which is unhelpful as it doesn’t indicate what they are actually referring to. Ask them whether they mean bits or bytes and you'll never be misled again.

Speeds

Speed is always denoted by time, typically written in seconds. All internet speeds should be written as 'Mbps' and not 'Mb' because without specifying the time taken, it's a size, not a speed.

It's important to remember that internet speeds are very, very rarely as fast as they say they are. An 8Mbps line means that under the best circumstances (i.e. you live inside a telephone exchange box and don’t share your line with anyone), you will get 8Mbps.

In reality, speeds are usually a lot lower. A download time is affected by many things: Line sharing (also known as contention ratio), time of day, distance from telephone exchange and quality of wiring (in your house and in the street) all factor into your actual broadband speed.

If you have a connection with a speed 'up to 8Mbps', it's practically impossible to actually get your full 8Mbps. Optimistically, you'll get about 4Mbps, and usually, it'll probably be around 2Mbps. This isn't always the fault of the provider; it typically depends on who you are connecting to and where they are.

The exception to this is if you're using a fibre to the premises broadband service, which is unaffected by the distance you live from the exchange. Even with this more reliable kind of connection, however, your speed will still be impacted by the number of customers using the service at any one time.