Data Transfer Rate Converter

About this Data Transfer Rate Converter

The Data Transfer Rate Converter translates network and file-transfer speeds between bit-based and byte-based units. It is useful when an internet connection is advertised in Mbps but a download application reports MB/s.

Internet service providers advertise connection speeds in bits per second (like Mbps), but file sizes on your computer are measured in bytes, and since one byte equals 8 bits, a 100 Mbps connection downloads at a theoretical maximum of about 12.5 megabytes per second, not 100.

For related tasks, try Data Storage Converter, Frequency Converter or Length Converter.

How the calculation works

The calculator uses decimal networking prefixes: K = 1,000, M = 1,000,000 and G = 1,000,000,000. Byte-based values are converted using eight bits per byte.

How to use it

1. Enter a transfer rate.
2. Choose the source and target rate units.
3. Convert to see the equivalent speed.

Practical example

80 Mbps equals 10 MB/s before protocol overhead because eight bits equal one byte.

A 50 Mbps internet plan converts to a theoretical maximum of 6.25 megabytes per second (50 / 8), meaning a 1,000 megabyte (1 GB) file would take at least about 160 seconds to download under ideal, uninterrupted conditions.

Things to double-check

Real-world download speeds are almost always noticeably lower than the theoretical maximum calculated from the advertised connection speed, due to network overhead and server-side limits, so treat a converted value as a ceiling rather than a guaranteed real-world speed.

Bits and bytes per second

Internet speeds are quoted in bits per second, such as megabits per second (Mbit/s), while downloads usually show bytes per second. Divide megabits by 8 to get megabytes: 100 Mbit/s is 12.5 MB/s. A 1 GB file at that speed would take about 80 to 82 seconds in ideal conditions, since 1 GB is about 8,000 to 8,192 megabits depending on how you count. Real transfers take longer, which is explained by overhead and congestion.

Why real speeds are lower

The speed on the plan is a maximum, and several things reduce what you actually get. Protocol overhead takes a share of the bandwidth, Wi-Fi signal strength falls with distance and walls, the other end of the connection may be slower, and other devices on your network compete for capacity. Expect typically 80 to 95 percent of the advertised speed on a wired connection and less on Wi-Fi. Test with a wired connection to see what your line really delivers.

Streaming and video calls

A rough guide is that standard video needs a few megabits per second, high definition streaming commonly needs around 5 Mbit/s, and 4K streams often need 15 to 25 Mbit/s. A video call uses roughly 1 to 4 Mbit/s each way. If several people in a home stream at once, add the requirements together and leave a margin. Upload speed matters for video calls and cloud backup, and is often much lower than download speed on home plans.

Estimating download times

To estimate a download, convert the file size to megabits and divide by your speed. A 700 MB file is 5,600 megabits, so on a 20 Mbit/s connection it takes about 280 seconds, or just under five minutes. Add a margin for overhead. For large downloads, such as game updates, a faster plan or wired connection saves a lot of time. Remember that data caps on mobile plans count the file size in bytes, not the speed.

Bandwidth and latency

Speed in megabits per second is bandwidth, the width of the pipe. Latency is the delay of a single message, measured in milliseconds, and it is a different thing. Large downloads and video streams depend on bandwidth, while online games and video calls depend more on low latency, with a ping under about 50 milliseconds generally feeling responsive. A fast connection with high latency can feel slow for gaming, and a modest connection with low latency can be perfectly good. Check both numbers when you test your connection.

Worked example: downloading a game update

A game update of 8 gigabytes on a 25 megabit per second connection takes about 43 minutes in ideal conditions. Eight gigabytes is about 65,536 megabits using binary units, and dividing by 25 gives roughly 2,621 seconds. Real transfers usually take 10 to 20 percent longer because of overhead and other traffic, so plan for around 50 minutes. On a 100 megabit connection the same file takes about 11 minutes, and on a gigabit connection about a minute. Working out the time in advance helps you schedule large downloads for the night and avoid starting them just before you need the file.

Wi-Fi, cables and device ports

Advertised speeds are theoretical maxima. A gigabit Ethernet cable moves up to 1,000 megabits a second, or 125 megabytes a second, and usually gets close to it. Wi-Fi shares the airwaves, loses speed with distance and walls, and often delivers half or less of the headline figure. USB 3.0 is rated at 5 gigabits per second, which is about 625 megabytes per second in theory, but the drive at the other end is often the limit. When a transfer is slower than expected, test with a cable, move closer to the router and check what other devices are using the network.

Data use for streaming and calls

To plan a mobile data allowance, estimate how much common activities use. Streaming video in standard quality may use around 0.7 gigabytes an hour, high definition about 3 gigabytes and ultra high definition up to about 7 gigabytes, although services vary. A video call typically uses 0.5 to 1.5 gigabytes an hour, and music streaming around 0.1 gigabyte an hour. On a 20 gigabyte monthly plan, that is only about 6 hours of high definition video. Use Wi-Fi where possible, lower the quality on mobile data and turn off automatic video playback.

Reading a speed test

A speed test reports download speed, upload speed and latency, sometimes with jitter, the variation in latency. Download speed matters for streaming and browsing, upload speed for video calls and backups, and latency for gaming and calls. For a fair result, use a wired connection, close other programmes and run the test several times at different hours, since evening peaks can slow a shared network. If your results are far below your plan, contact the provider with the test results and the times you ran them, and check that your router is not the weak link.

Key terms explained

Bandwidth is the maximum amount of data that a connection can carry per second. Throughput is the actual rate achieved. A bit per second is the basic unit, with kilobits, megabits and gigabits as multiples, and a byte per second is eight times larger. Latency is the delay of a message, and jitter is the variation in that delay. Download is data coming to you and upload is data sent from you. Overhead is the extra data used by protocols, and congestion happens when many users share a link.

Rules of thumb and quick checks

Divide megabits by eight to get megabytes per second: 80 megabits per second is 10 megabytes per second. A file of 1 gigabyte takes about 80 seconds at 100 megabits per second and about 8 seconds at 1 gigabit, before overhead. Expect real speeds of 80 to 95 percent of the rated figure on a wired connection. If a download is much slower than your plan, test with a cable, close other devices and try at a different time.

Frequently asked questions