MB/s to Mbps Converter

MB/s to Mbps — quick reference

The formula, worked line by line

One multiplication by eight, because there are eight bits in a byte. The arithmetic takes a second; the reason to do it is that without it the two most important numbers about your connection are in units that cannot be compared.

Once that sentence is internalised the rest of the page is detail. The conversion is the diagnostic, and it clears the most likely explanation before any harder ones are considered.

Mbps = MB/s x 8
MB/s = Mbps / 8
12.5 MB/s x 8 = 100 Mbps
117.5 MB/s x 8 = 940 Mbps
realistic MB/s = (plan Mbps x 0.94) / 8

Where the missing few percent goes

Every packet carries headers, and the receiver sends acknowledgements back along the same link. Over wired Ethernet with TCP the payload typically occupies about 94 percent of the raw capacity. Wireless adds its own framing and contention, and a shared or congested path adds more still.

Reading a speed test correctly

If you keep one number from this page, keep 12.5. A hundred megabits per second is twelve and a half megabytes per second, and recognising that figure on screen is usually enough to end the question before it starts.

How to use the MB/s to mbps converter

Multiply by eight. That is the whole conversion, and it is the single most useful piece of arithmetic anyone can learn about their internet connection, because it is the only way to compare what you are watching against what you are paying for.

The two numbers are almost never in the same unit. Providers sell bandwidth in megabits per second because the number is eight times larger and looks better on a price list. Browsers, download managers and file transfer tools report megabytes per second because a file is measured in bytes. Neither is being deceptive; they are just not comparable until one moves.

The complaint this conversion resolves is extremely common and almost always unfounded. Somebody upgrades to 100 Mbps, starts a download, sees 11 or 12 in the progress window, and concludes they are getting an eighth of what they bought. They are getting all of it. The unit changed on the way from the contract to the screen.

To draw a real conclusion you want a steady rate on a large transfer from somewhere fast, over a cable rather than wireless. Multiply that by eight and compare to the plan. Landing within about ten percent is normal; landing at an eighth means you compared the wrong units, and landing at a half usually means the wireless link, not the service.

Working out whether the line is actually slow

Once the units agree you can start eliminating causes, and the order matters because each step is cheaper than the one after it. The conversion is step zero: about half of all reported slowness turns out to be the factor of eight and needs no further investigation at all.

If the cabled test is also low, the next thing to check is whether the transfer itself is representative. Try a large file from a well-known fast source. If that is fast and your original download was not, the limit was at the other end.

Why the two industries never agreed

Transmission has always been measured in bits because a link sends one bit at a time, and its capacity is naturally described that way regardless of how a receiving machine groups them. Storage has always been measured in bytes because that is the smallest addressable unit a file is made of. Both conventions predate the internet and neither had reason to change.

The one thing worth being suspicious about is a figure that is consistently eight times too low across many sources, on a cable, over days. That is not a unit problem and it is not a server problem. That is worth a call to the provider, and having the converted figure in the unit they sold you makes the conversation considerably shorter.

Every MB/s value, worked out

139 common MB/s figures each get their own page, with the answer, the arithmetic, what rounding costs, and the nearest real-world reference point on the scale.

Questions people ask