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Network Speed Unit Converter

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入力

自動処理

Bit Rate Units (Decimal – Powers of 1000)

bits per second (bps)

kilobits/sec (Kbps)

megabits/sec (Mbps)

gigabits/sec (Gbps)

terabits/sec (Tbps)

Byte Rate Units (Decimal – Powers of 1000)

bytes/sec (B/s)

kilobytes/sec (KB/s)

megabytes/sec (MB/s)

gigabytes/sec (GB/s)

terabytes/sec (TB/s)

Byte Rate Units (Binary – Powers of 1024)

kibibytes/sec (KiB/s)

mebibytes/sec (MiB/s)

gibibytes/sec (GiB/s)

tebibytes/sec (TiB/s)

小数点精度

クイック選択

出力

クライアント側

Real-World Speed Reference

Connection / Interface	Bit Rate	Byte Rate
Dial-up modem	56 Kbps	7 KB/s
3G mobile	2 Mbps	250 KB/s
4K video stream (Netflix)	25 Mbps	3.13 MB/s
4G LTE (typical)	50 Mbps	6.25 MB/s
Home cable broadband	300 Mbps	37.5 MB/s
USB 2.0 (high speed)	480 Mbps	60 MB/s
Gigabit Ethernet	1 Gbps	125 MB/s
5G mobile (mid-band)	1 Gbps	125 MB/s
USB 3.0 / Wi-Fi 6 (per stream)	5 Gbps	625 MB/s
SATA III SSD	6 Gbps	750 MB/s
10 Gigabit Ethernet	10 Gbps	1.25 GB/s
USB 3.2 Gen 2x2	20 Gbps	2.5 GB/s
Thunderbolt 4 / USB4	40 Gbps	5 GB/s
NVMe SSD (PCIe 4.0 x4)	64 Gbps	8 GB/s
Thunderbolt 5	80 Gbps	10 GB/s

Bits vs Bytes: The Source of Confusion

Network and Internet speeds are typically advertised in bits per second (bps), while file sizes and download speeds in your browser are usually shown in bytes per second (B/s). 1 byte = 8 bits, so a "100 Mbps" connection downloads at most about 12.5 MB/s, not 100 MB/s.

小文字 空白（文字なし） = bit, uppercase B = byte. So Mbps (megabits/sec) and MB/秒 (megabytes/sec) differ by a factor of 8.

SI units (KB, MB, GB) use powers of 1000 and are standard for networking. Binary units (KiB, MiB, GiB) use powers of 1024 and are sometimes used by operating systems when reporting transfer rates.

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ガイド

Network Speed Unit Converter

Instantly convert between every common network and data transfer rate unit – bps, Kbps, Mbps, Gbps, Tbps, B/s, KB/s, MB/s, GB/s, TB/s, plus the binary IEC units like KiB/s and MiB/s. Type a value into any field and every other field updates live, so you never have to guess whether a “100 Mbps” connection is actually 100 MB/s (it is not – it is 12.5 MB/s).

使用方法

Type a value into any of the rate inputs – bits, bytes, or binary units.
Every other unit updates instantly with the converted value.
Click a クイック選択 chip to load a common speed (dial-up, gigabit, USB 3.0, Thunderbolt 4, NVMe, and more).
調整 小数点精度 to control how many digits to display after the decimal point.
プレビューするには すべてコピー to copy every unit and value at once, or click the copy icon next to any individual field.

機能

Bit rates – bps, Kbps, Mbps, Gbps, Tbps (powers of 1000).
Byte rates – B/s, KB/s, MB/s, GB/s, TB/s (powers of 1000).
Binary byte rates – KiB/s, MiB/s, GiB/s, TiB/s (powers of 1024) for OS-style reporting.
Live conversion – edit any field and every other updates immediately, no submit button.
クイック選択 chips for common speeds: 56 Kbps dial-up, 100 Mbps cable, 1 Gbps gigabit, 5 Gbps USB 3.0, 10 Gbps 10GbE, 40 Gbps Thunderbolt 4, 80 Gbps Thunderbolt 5.
Real-world reference table – matches popular interfaces and connections to their bit and byte rates.
設定可能な精度 – choose from 0 to 10 decimal places.
Copy individual or all values to clipboard with one click.

Bits vs Bytes Made Simple

Internet and network speeds are advertised in bits per second (lowercase b: bps, Mbps, Gbps). File sizes and download speeds in your browser and operating system are usually shown in bytes per second (uppercase B: B/s, MB/s, GB/s). One byte is eight bits, so divide bit rates by 8 to get the maximum achievable byte transfer rate. A 100 Mbps connection downloads at up to 12.5 MB/s, a 1 Gbps fiber line at up to 125 MB/s, and a 10 Gbps interface at up to 1.25 GB/s.

When to Use Which Unit

ISP advertising and link speed – bits per second (Mbps, Gbps).
Browser, FTP, and download manager progress – bytes per second (KB/s, MB/s).
Operating system file transfer dialogs – often binary bytes (MiB/s, GiB/s).
USB, Thunderbolt, PCIe, SATA, NVMe interface specs – bits per second (Gbps).
Disk benchmarks (CrystalDiskMark, fio) – bytes per second (MB/s, GB/s).

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 よくある質問

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

Because Mbps means megabits per second and MB/s means megabytes per second. One byte is eight bits, so dividing the advertised bit rate by 8 gives the theoretical maximum byte rate. A 100 Mbps connection has a ceiling of 12.5 MB/s, and real-world overhead from TCP/IP headers and protocol handshakes typically reduces that further to around 11–12 MB/s.
What is the difference between Mbps and MiB/s?

Mbps is megabits per second using powers of 1000 (1 Mbps = 1,000,000 bits/sec). MiB/s is mebibytes per second using powers of 1024 (1 MiB = 1,048,576 bytes). Mbps is the standard for networking and ISP marketing, while MiB/s is the binary unit used by many operating systems when displaying file transfer speeds.
Why do USB and Thunderbolt specs always use Gbps instead of GB/s?

Hardware interface specifications historically describe the raw signaling rate on the physical wire, which is naturally measured in bits per second. The bus also carries encoding overhead (such as 8b/10b or 128b/132b line codes), so the usable byte throughput is always lower than a simple divide-by-8. For example, USB 3.0 runs at 5 Gbps signaling but delivers about 500 MB/s of usable data, not 625 MB/s.
How are SI (decimal) and IEC (binary) units related for transfer rates?

SI units use powers of 1000: 1 KB = 1,000 bytes, 1 MB = 1,000,000 bytes. IEC units use powers of 1024: 1 KiB = 1,024 bytes, 1 MiB = 1,048,576 bytes. The difference compounds at higher scales – 1 TB equals about 0.909 TiB. Networking and storage manufacturers use SI; operating systems often use IEC, which is why a 500 GB drive shows as roughly 465 GiB.