How to use the Data Transfer Rate Converter
- Convert units: enter a value, pick the from and to units, or tap a common pair such as Mbps → MB/s. Every other unit is listed below.
- Download time: enter the file size and your connection speed (or pick a plan, USB or Ethernet preset) and set the overhead.
- Speed needed: enter a file size and the time you have, and get the connection speed required.
What does this tool do?
Network speeds are quoted in bits per second, file sizes and download meters in bytes — and a byte is 8 bits. That's why a 100 Mbps plan tops out around 12.5 MB/s, and why a 1 GB file takes at least 80 seconds rather than 10 on that connection.
Two prefix systems add to the confusion. Decimal units (kB, MB, GB) use multiples of 1,000 and are what ISPs, network gear and drive makers use; binary units (KiB, MiB, GiB) use 1,024 and are what Windows shows, even though it labels them “MB”. The converter covers both, plus usage units such as GB per hour and TB per month for data caps and streaming.
Real transfers never reach the line rate, because TCP/IP headers, encryption, Wi-Fi and retransmissions use part of it. The download-time calculator applies an overhead you can adjust — around 5–10% on a good wired link, more on busy Wi-Fi — and shows the theoretical best alongside, plus the same file at common speeds.
Why use it?
- 19 units: bits, bytes, binary (KiB/MiB/GiB) and per-hour/day/month usage.
- Realistic download and copy times with adjustable overhead.
- Presets for internet plans, Ethernet, USB, Thunderbolt, SATA and NVMe.
- Works backwards: the speed you need for a deadline.
- Every unit listed at once, with copy-ready results.
Use cases
- Checking whether a broadband plan is fast enough for large game or video downloads.
- Estimating how long a backup or cloud upload will take overnight.
- Comparing USB 3, Thunderbolt and network transfers for moving big files.
- Converting streaming bitrates into GB per hour against a data cap.
Example: a 50 GB game on a 300 Mbps plan
300 Mbps is 37.5 MB/s. With 10% overhead the effective speed is about 33.75 MB/s, so 50 GB (50,000 MB) takes around 24 minutes 41 seconds — compared with 22 minutes 13 seconds in theory.
| Advertised speed | Max MB/s | 1 GB file (10% overhead) |
|---|---|---|
| 25 Mbps | 3.125 MB/s | 5 min 56 s |
| 100 Mbps | 12.5 MB/s | 1 min 29 s |
| 300 Mbps | 37.5 MB/s | 30 s |
| 1 Gbps | 125 MB/s | 8.9 s |
Common mistakes
- Treating Mbps and MB/s as the same. The lower-case b means bits; MB/s is eight times larger.
- Expecting the advertised speed. Plans are “up to” a line rate measured before overhead, and the server, Wi-Fi and other devices can be the real limit.
- Mixing binary and decimal sizes: a “4.7 GB” file in Windows is about 5.05 GB in decimal units.
- Forgetting upload speed. Many home connections upload 5–20× slower than they download, which matters for backups and video calls.
The formula
Privacy
The calculation happens instantly in your browser. The numbers you enter are not sent to our servers or saved. There's no account to create and nothing to install.
Frequently asked questions
How do I convert Mbps to MB/s?
Divide by 8. 100 Mbps ÷ 8 = 12.5 MB/s, 500 Mbps = 62.5 MB/s and 1 Gbps (1,000 Mbps) = 125 MB/s.
Why is my download speed slower than my internet speed?
Mostly because downloads show bytes per second while plans are sold in bits per second. On top of that, protocol overhead takes about 5–10%, and the server, Wi-Fi signal or other devices on your network can slow things further.
How long does it take to download 1 GB?
At 100 Mbps, about 80 seconds in theory and roughly 1½ minutes in practice. At 25 Mbps allow about 6 minutes; on gigabit fibre, around 9 seconds.
Is 1 Gbps the same as 1 GB/s?
No. 1 Gbps (gigabit per second) is 125 MB/s; 1 GB/s (gigabyte per second) is eight times faster.
What is a MiB/s?
A mebibyte per second: 1,048,576 bytes per second, about 4.9% more than 1 MB/s. Many operating systems use binary units like this when showing transfer speeds and file sizes.
How much data does a 25 Mbps stream use per hour?
25 Mbps × 3,600 seconds ÷ 8 = 11,250 MB, or about 11.25 GB per hour. Use the GB/hour unit to convert any bitrate.
Last reviewed by the M2Toolkit team.