Megabit to Gibibit

Divide Mbps by 8 to get megabytes per second (MB/s). A 100 Mbps connection = 12.5 MB/s. A 1 Gbps connection = 125 MB/s. This conversion is essential when comparing advertised internet speeds (always in Mbps) to actual file download speeds (shown in MB/s by browsers and download managers).

Netflix recommends 25 Mbps for 4K Ultra HD. Disney+ and Apple TV+ recommend 25 Mbps; YouTube recommends 20 Mbps for 4K. These are per-stream figures — a household streaming two 4K sources simultaneously needs roughly 50 Mbps of reliable throughput, plus headroom for other devices.

ISP speed ratings are theoretical maximums under ideal conditions. Real-world factors include network congestion, router quality, Wi-Fi interference, the server's upload speed, and protocol overhead. Additionally, browsers and download managers report speeds in MB/s (bytes), which is 8× smaller than the Mbps figure — a 100 Mbps plan showing 11 MB/s in a browser is performing normally.

One gigabit equals 1,000 megabits (SI decimal system). Gigabit broadband (1 Gbps) = 1,000 Mbps = 125 MB/s theoretical download speed. In the binary IEC system, one gibibit = 1,024 mebibits — but for internet speeds the SI decimal values are always used.

Fiber-to-the-home (FTTH) delivers symmetric speeds of 100–10,000 Mbps with consistent performance regardless of distance from the exchange. Cable (DOCSIS 3.1) offers 100–1,200 Mbps download but typically 10–50 Mbps upload, and throughput degrades during neighborhood peak hours due to shared bandwidth. DSL (VDSL2) maxes out at 50–100 Mbps download and drops sharply beyond 500 meters from the DSLAM cabinet. In practice, most cable users see 60–80% of advertised speeds; DSL users at distance may see under 50%. Fiber is the only technology that reliably delivers its rated megabit throughput.

A gigabit (Gbit) = 10⁹ bits = 1,000,000,000 bits (SI). A gibibit (Gibit) = 2³⁰ bits = 1,073,741,824 bits (IEC binary). The difference is 7.37%. Consumer networking equipment and ISP speed ratings use decimal gigabits; memory and chip designers sometimes use gibibits when binary precision is required.

Virtually all networking equipment — routers, switches, NICs, ISP speed ratings — uses decimal gigabits (Gbit). A "1 Gbps" (gigabit per second) connection means exactly 1,000,000,000 bits per second, not 1,073,741,824 bits per second. Network standards (Ethernet IEEE 802.3) are defined in SI units.

DDR memory bandwidth is calculated from clock speed, bus width, and transfers per clock. A DDR5-4800 module on a 64-bit bus delivers 4,800 MT/s × 64 bits = 307,200 Mbit/s ≈ 292.97 Gibit/s. Engineers use gibibits when verifying that memory throughput matches binary-aligned cache line sizes (typically 512 bits = 64 bytes), ensuring no fractional transfers occur during burst reads.

GPU memory bandwidth is typically quoted in gigabytes per second (GB/s) using SI decimal values — not gibibits. For example, NVIDIA's RTX 4090 has 1,008 GB/s of memory bandwidth (decimal). Some academic papers and IEEE publications convert this to GiB/s or Gibit/s for precision, but consumer GPU marketing universally uses SI decimal units.

Gibibit appears in: IEEE standards documents specifying memory interface speeds, JEDEC memory specifications, some academic networking papers, and storage controller datasheets. Consumer-facing software, marketing materials, and OS interfaces virtually never display gibibits — they show gigabits (networking) or gigabytes (storage). It is primarily a precision engineering unit.