What this calculator does
Internet speeds are quoted in megabits per second (Mbps), but file sizes are measured in megabytes (MB), and the two units are easy to mix up because they look almost identical in text. Since a byte is 8 bits, converting Mbps to MB/s means dividing by 8: a 100 Mbps connection transfers at roughly 12.5 MB/s under ideal conditions.
The confusion causes real disappointment: someone sees "100 Mbps" advertised, expects a 100 MB file to download in one second, and is confused when it takes closer to eight. The connection is not underperforming, the units were just never the same to begin with.
The formula
To go from Mbps to MB/s, divide by 8, since there are 8 bits in a byte. To go the other way, from MB/s to Mbps, multiply by 8.
| Term | Meaning |
|---|---|
| Mbps | Megabits per second, the unit internet and network speeds are almost always advertised in. |
| MB/s | Megabytes per second, the unit file sizes and download progress are usually shown in. |
The inputs explained
| Field | What to enter |
|---|---|
| Convert | Choose which direction to convert. |
| Value | The speed value to convert, in whichever unit matches the direction chosen above. |
When to use it
Estimating a real download speed
An advertised or measured Mbps figure converts to MB/s to match the units a download manager or browser typically displays progress in.
Reading a router or ISP speed test result
Speed tests report in Mbps by convention; converting to MB/s makes it directly comparable to a file size in megabytes.
Checking a file transfer estimate
A download manager reporting MB/s can be converted back to Mbps to compare against an advertised connection speed.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
What is a given Mbps speed in MB/s?
Common advertised connection speeds converted to megabytes per second.
| Speed | MB/s |
|---|---|
| 25 Mbps | 3.125 MB/s |
| 50 Mbps | 6.250 MB/s |
| 100 Mbps | 12.500 MB/s |
| 250 Mbps | 31.250 MB/s |
| 500 Mbps | 62.500 MB/s |
| 1000 Mbps | 125.000 MB/s |
Questions
Why is internet speed measured in bits and not bytes?
It is a long-standing networking convention going back to how data is physically transmitted, one bit at a time down a wire or through the air. File sizes, by contrast, have always been measured in bytes, the unit a computer actually stores and processes data in.
Will I actually get the full converted speed in practice?
Rarely. Real-world throughput is usually somewhat below the theoretical maximum because of network overhead, contention with other devices, server-side limits and other factors, so treat the converted figure as a ceiling rather than a guarantee.
Is a capital B always bytes and lowercase b always bits?
That is the standard convention (Mbps for megabits, MB/s for megabytes) and this calculator follows it, but it is worth double-checking the source of any figure you are converting, since the convention is not universally followed in casual use.
How is this different from a download time calculator?
This page is a straight unit conversion between two speed units. A download time calculator additionally takes a file size and works out how long a transfer takes at a given speed.
To work out how long a specific file actually takes to download or upload at a given speed, see the Mbps download time calculator.