**As Australian telcos deliver the idea of “unlimited data” with the megabit catch, you might be pondering a question: what exactly is a megabit?**

A unit of measurement for network speeds, a megabit is distinct from a megabyte. While they sound similar, a megabit — often written as Mbps or “Megabits per second” — details the speed, while megabyte — written as MB/s or “Megabytes per second” — indicates the file transfer rate.

Generally, a megabit speed is well over what the megabyte speed would be, so if you’re trying to work out how fast your internet connection is measured in megabytes per second, you take the megabit speed and divide by eight.

For instance, a transfer speed of 250 megabits is divided by 8 to find out that 250Mbps transfers at 31.25 megabytes per second (MB/s).

## What’s a gigabit?

The same is true with gigabits, because while the gigabit seems like it might also be a gigabyte, one is about transfer speed while the other is about transfer size.

As the first gigabit networks start to switch on around the world, it may seem easy to believe that a one gigabit connection is transferring at one gigabyte per second, but that’s not what you’re seeing.

Instead, use the same logic: take the gigabit speed and divide by eight.

For instance, a gigabit speed of 1 gigabit (1Gbps) is also 1000Mbps, which you can divide by eight to find the answer: 1000Mbps divided by eight equals 125 megabytes per second.

## Why one megabit isn’t fast

When Australian telcos rolled out their “unlimited internet deals” for 4G phone plans, many came with a catch: once you hit a certain amount of data, the 4G speeds would drop to 1.5 megabit per second for the rest of the month.

Based on this learning, you can work out that a 1.5 megabit maximum is not a 1.5 megabyte maximum. Far from it, in fact.

Rather, 1.5Mbps again is divided by eight, and that leave you not with megabytes, but kilobytes, making the maximum speed 187 kilobytes per second, or to put it bluntly, just short of a fifth of a megabyte per second.

Given 4G speeds tend to range between 25 megabits per second and reach as high as 1200 megabits per second, this is a staggering drop, and obviously won’t deliver services at the same speed.

As such, if you’ve wondered why the Australian so-called unlimited services have been called into question so much by media, this lack of service speed is one of the obvious reasons.