What Does Mbps Mean?
Mbps means megabits per second: how many million bits of data your connection moves each second. It’s the standard unit for internet speed. File sizes use megabytes (MB) instead, and since 1 byte is 8 bits, divide Mbps by 8 to get MB per second: 100 Mbps ≈ 12.5 MB/s.
Mbps vs MB/s: the lowercase b matters
- Mbps (or Mb/s), lowercase b: megabits per second. Used by internet providers and speed tests.
- MB/s (or MBps), uppercase B: megabytes per second. Used by browsers, Steam and download managers.
One megabyte is 8 megabits. That’s why a “100 Mbps” plan shows downloads of about 11–12 MB/s in Steam or Chrome. Nothing is wrong; it’s the same speed in different units.
Quick conversion table
| Internet speed | Download rate |
|---|---|
| 10 Mbps | 1.25 MB/s |
| 25 Mbps | 3.1 MB/s |
| 50 Mbps | 6.25 MB/s |
| 100 Mbps | 12.5 MB/s |
| 300 Mbps | 37.5 MB/s |
| 500 Mbps | 62.5 MB/s |
| 1 Gbps (1,000 Mbps) | 125 MB/s |
In practice expect about 5–10% less, because some of every connection is used by networking overhead.
How long will a download take?
The formula is: file size in MB × 8 ÷ speed in Mbps = seconds. Here’s what that looks like for common file sizes:
| File | 25 Mbps | 100 Mbps | 500 Mbps |
|---|---|---|---|
| Song (5 MB) | 2 sec | under 1 sec | instant |
| HD movie (4 GB) | 21 min | 5 min 20 sec | 1 min |
| Phone backup (20 GB) | 1 h 47 min | 27 min | 5 min 20 sec |
| Big game (100 GB) | 8 h 53 min | 2 h 13 min | 27 min |
Kbps, Mbps and Gbps
- Kbps: kilobits per second (thousands). Old dial-up ran at 56 Kbps.
- Mbps: megabits per second (millions). Most home plans are 25–1,000 Mbps.
- Gbps: gigabits per second (billions). 1 Gbps = 1,000 Mbps, typical of fibre plans.
Why do providers use bits instead of bytes?
Networks have always measured data in bits, because data travels one bit at a time down the line. It also makes the numbers look 8× bigger, which providers don’t mind. Whatever the reason, compare plans and speed tests in Mbps, and divide by 8 when you want to know how fast a file will download.
What Mbps should you have?
For most households, 100 Mbps download and 20 Mbps upload is comfortable. The full breakdown by activity and household size is in what is a good internet speed. To see your own number, run the WiFi speed test.