Calculators
Mbps to MB/s calculator and download time
Internet plans are sold in megabits per second, while browsers and download managers show megabytes. This calculator converts between them and estimates the download time for any file size.
Everything is calculated in your browser: your input is not sent or stored.
How we calculate
Megabits to megabytes
MB/s = Mbps / 8
Download time
time = size_MB / (Mbps / 8 · (1 − overhead))
- A byte has 8 bits, so a 300 Mbps plan tops out at 37.5 MB/s.
- Overhead is protocol data for TCP/IP, Wi-Fi and encryption — usually 5–10%. The default is 7%; adjust the slider.
- MB vs MiB: ISPs and drive makers use decimal units (1 GB = 1000 MB), while Windows shows binary ones (1 GiB = 1024 MiB ≈ 1.074 GB). Tick the box if your size comes from Windows Explorer.
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Frequently asked questions
How many MB/s is 100 Mbps?
12.5 MB/s in theory, about 11.5–12 MB/s after overhead.
Why is my download slower than my plan?
Plans are in megabits, downloads in megabytes — eight times smaller. Network overhead, Wi-Fi and the server's own speed take their share too.
How long does a 100 GB game take on 300 Mbps?
About 48 minutes with 7% overhead.
What's the difference between MB and MiB?
An MB is one million bytes, an MiB is 1,048,576 bytes. Windows labels MiB as “MB”, so files look smaller there.