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Bandwidth Converter — Mbps ↔ MB/s, Gbps, Kbps

Convert between Mbps, MB/s, Gbps, Kbps and other network speed units. Includes a bit-vs-byte cheatsheet and estimated download times for common file sizes. 100% local.

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bits / second (SI)

How ISPs and network hardware advertise speed.

bpsbit / s100,000,000
kbpskbit / s100,000
MbpsMbit / s100
GbpsGbit / s0.1
TbpsTbit / s1.000e-4

bytes / second (SI)

How your browser / download client displays speed.

BpsByte / s12,500,000
KBpsKB / s12,500
MBpsMB / s12.5
GBpsGB / s0.0125
TBpsTB / s1.250e-5

IEC (×1024)

Binary variant — rare in networking, common in benchmark tools.

KibpsKibit / s97,656.25
MibpsMibit / s95.3674
GibpsGibit / s0.093132
KiBpsKiB / s12,207.03
MiBpsMiB / s11.9209
GiBpsGiB / s0.011642

Estimated download time

Assuming a perfect link, no protocol overhead.

100 MB(photo folder)8.0 s
1 GB(movie, SD)1.3 min
5 GB(game demo)6.7 min
50 GB(4K movie)1.1 h
Big-B vs small-b matters: 100 Mbps (megabit / s) is the same speed as 12.5 MB/s (megabyte / s). ISPs advertise the bigger number in bits; your download progress bar shows the smaller number in bytes. Rule of thumb: divide the bit-per-second speed by 8 to get the byte-per-second speed you actually see in a download UI.

Frequently Asked Questions

Why is my 100 Mbps connection only downloading at 12 MB/s?

It's not slow — that's exactly the correct speed. ISPs advertise in megabits (100 Mbps) and browsers display in megabytes (12.5 MB/s). 1 Byte = 8 bits, so divide the bit-per-second number by 8 to get the byte-per-second number you see in a download UI.

When would I ever use MiBps or Kibps?

Almost never for networking — network speeds are conventionally quoted in SI decimal units (×1000). IEC binary units for bandwidth show up mostly in disk-throughput benchmarks and some professional storage tooling. Everyone else uses Mbps / MB/s.

Do these download time estimates account for TCP overhead?

No — they assume a perfect link. Real-world downloads lose 3–15% to protocol overhead (TCP headers, TLS handshakes, HTTP framing) and can be much slower over Wi-Fi or a congested link. Use the estimate as a best-case ceiling.

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