How fast can a 300 Mbps connection download?

In theory 300 ÷ 8 = 37.5 MB/s. In practice it is a little lower, because TCP/IP headers, retransmission, and encryption all use bandwidth; seeing 33 to 36 MB/s is normal.

Why are network speeds in bits rather than bytes?

It is a telecoms convention: transmission is specified and priced per bit at the circuit level, so bps carried over to networking. File sizes use bytes because memory and storage are byte-addressed. Two industry conventions, and a factor of eight between them.

UNIT CONVERSION · CALCULATED FROM DEFINITIONS

Mbps to MB/s Converter

Turn a quoted network speed into the download rate you actually see.

From

Network speeds are quoted in bits, not bytes

Usually what a download client displays

FormulaMB/s = Mbps × 0.125

Ratio1 Mbps = 0.125 MB/s

Every unit in this category

bps1,000,000Bits per second

kbps1,000Kilobits per second

Gbps0.001Gigabits per second

KB/s125Kilobytes per second

MB/s0.125Megabytes per second

MiB/s0.11920929Mebibytes per second

Common values

Mbps	MB/s
`0.5 Mbps`	`0.0625 MB/s`
`1 Mbps`	`0.125 MB/s`
`2 Mbps`	`0.25 MB/s`
`3 Mbps`	`0.375 MB/s`
`5 Mbps`	`0.625 MB/s`
`10 Mbps`	`1.25 MB/s`
`15 Mbps`	`1.875 MB/s`
`20 Mbps`	`2.5 MB/s`
`25 Mbps`	`3.125 MB/s`
`30 Mbps`	`3.75 MB/s`
`50 Mbps`	`6.25 MB/s`
`75 Mbps`	`9.375 MB/s`
`100 Mbps`	`12.5 MB/s`
`150 Mbps`	`18.75 MB/s`
`200 Mbps`	`25 MB/s`
`500 Mbps`	`62.5 MB/s`
`1000 Mbps`	`125 MB/s`

About this tool

Enter the Mbps figure from your plan and get the MB/s a download client will show. Network speeds are quoted in bits and download clients report bytes, a factor of eight — which is the whole explanation for "why does my 300M fibre only reach 37 MB/s". Other rate units are listed alongside, with a reminder that protocol overhead takes another 5% to 10% off in practice.

How it works

Enter the Mbps figure quoted for your plan.
Read the matching MB/s download rate.
Check the table for other rate units and common plans.

Precision and definitions

One byte is eight bits. The conversion excludes protocol overhead, so real downloads run slightly slower.

Privacy

Every conversion runs inside this browser. The values you enter are never uploaded, stored, or written to the URL or any log.

Frequently asked questions

How fast can a 300 Mbps connection download?: In theory 300 ÷ 8 = 37.5 MB/s. In practice it is a little lower, because TCP/IP headers, retransmission, and encryption all use bandwidth; seeing 33 to 36 MB/s is normal.
Why are network speeds in bits rather than bytes?: It is a telecoms convention: transmission is specified and priced per bit at the circuit level, so bps carried over to networking. File sizes use bytes because memory and storage are byte-addressed. Two industry conventions, and a factor of eight between them.

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