Gbps to MB/s Converter
Convert gigabits per second to megabytes per second. Multiply by 125, or work through Mbps if you prefer to keep the factor of 8 visible.
Why the multiplier is 125
Converting between giga-prefixed bits and mega-prefixed bytes crosses two boundaries at once: the prefix changes by 1,000 and the unit changes by 8. The two operations combine into a single multiplier of 1,000 ÷ 8 = 125.
1 Gbps = 1,000 Mbps (prefix step: × 1,000) 1 Mbps = 0.125 MB/s (bit to byte: ÷ 8) So 1 Gbps = 1,000 × 0.125 = 125 MB/s Direct form: MB/s = Gbps × 125 Gbps = MB/s ÷ 125
The same logic gives the multipliers for the neighbouring unit pairs: Mbps to MB/s is ×0.125, Gbps to Mbps is ×1,000, and MB/s to GB/s is ÷1,000. Only the gigabit-to-megabyte pair needs the 125.
What the theoretical figure means in practice
Multiplying by 125 gives the line rate, which assumes every bit on the wire carries payload. Real Ethernet frames spend bytes on framing, the IP header and the TCP header before any application data arrives, and TCP acknowledgements consume capacity in the return direction.
Example: a 10 GbE link
10 Gbps × 125 = 1,250 MB/s line rate
× 0.94 TCP efficiency ≈ 1,175 MB/s single stream
× 0.96 storage and PCIe ≈ 1,128 MB/s delivered to an application
Using jumbo frames raises the efficiency because the header cost is spread over 9,000 bytes instead of 1,500. That is why storage networks are usually configured with an MTU of 9,000 on every hop — the MTU/MSS calculator models the resulting overhead.
A single TCP stream often cannot reach 1,175 MB/s over a long path because the window size limits it. The TCP throughput calculator shows how much window is needed at a given round-trip time.
The 8× trap between networks and storage
Storage interfaces are specified in bytes per second and network interfaces in bits per second, and the resulting confusion is the most expensive unit error in infrastructure planning.
| Network link | MB/s equivalent | Matches this storage rate | Notes |
|---|---|---|---|
| 1 Gbps | 125 MB/s | 1 GB/s is 8× faster | One SATA SSD saturates it |
| 2.5 Gbps | 312.5 MB/s | About 0.3 GB/s | Common in NAS and access switches |
| 10 Gbps | 1,250 MB/s | 1.25 GB/s | One fast NVMe drive is comparable |
| 25 Gbps | 3,125 MB/s | 3.1 GB/s | Often used in storage fabrics |
| 40 Gbps | 5,000 MB/s | 5 GB/s | Older data-centre backbone |
| 100 Gbps | 12,500 MB/s | 12.5 GB/s | Modern spine and storage fabric |
Read the table as a pairing guide: a 10 GbE link and a 1.25 GB/s drive are matched, but a 1 GbE link to a 1 GB/s drive wastes seven eighths of the drive. Checking that both numbers are in the same unit before comparing them prevents this entirely.
Common mistakes
- Dividing by 8 instead of multiplying by 125. Dividing a Gbps figure by 8 gives megabits, not megabytes — the answer is off by a factor of 1,000 and will look absurdly small.
- Comparing Gbps against GB/s directly. They differ by eight times. A "10 Gb" switch is not equivalent to a "10 GB/s" interface; it is equivalent to 1.25 GB/s.
- Assuming the link is the bottleneck. At 10 Gbps and above, the CPU, PCIe lanes and storage array are frequently the limiting factor rather than the network.
- Forgetting that a full-duplex link is bidirectional. A 10 Gbps link delivers 10 Gbps in each direction simultaneously, so a backup that reads from one server and writes to another can use both directions at once.
Also: Mbps to MB/s Converter · MB/s to Mbps Converter · IP to Binary Converter · IP to Hex Converter · IP to Decimal Converter
Reference: gigabit link speeds
| Standard | Gbps | Mbps | MB/s (line rate) | Realistic single stream |
|---|---|---|---|---|
| 1000BASE-T | 1 | 1,000 | 125 | 112–118 MB/s |
| 2.5GBASE-T | 2.5 | 2,500 | 312.5 | 280–295 MB/s |
| 5GBASE-T | 5 | 5,000 | 625 | 560–590 MB/s |
| 10GBASE-T | 10 | 10,000 | 1,250 | 1,100–1,180 MB/s |
| 25GbE | 25 | 25,000 | 3,125 | 2,800–2,950 MB/s |
| 40GbE | 40 | 40,000 | 5,000 | 4,500–4,750 MB/s |
| 100GbE | 100 | 100,000 | 12,500 | 11,000–11,800 MB/s |
The realistic column assumes a single TCP stream with a tuned window, no packet loss and no competing traffic. It is limited by round-trip time as much as by the link, which is why a single stream from a distant server rarely reaches these figures. Multiple parallel streams can approach the line rate more closely, which is why backup and replication tools usually run several streams at once.
Related: Mbps to MB/s, MB/s to Mbps, bandwidth calculator, TCP throughput calculator.
Frequently asked questions
How do I convert Gbps to MB/s?
Multiply by 125. One gigabit per second is 1,000,000,000 bits per second, and dividing by 8 gives 125,000,000 bytes per second, which is 125 MB/s. The formula is MB/s = Gbps × 125.
Why is the multiplier 125 and not 8?
Because the units differ by two steps, not one. Converting gigabits to megabits multiplies by 1,000, and converting megabits to megabytes divides by 8. Combining the two gives 1,000 ÷ 8 = 125. If you prefer, multiply by 8 to reach Mbps and then divide by 8 — but those cancel, leaving 125.
How fast is 10 Gbps in MB/s?
1,250 MB/s theoretically, or about 1.25 GB/s. In practice a well-tuned 10 GbE link delivers 1,100 to 1,180 MB/s, with the shortfall coming from TCP/IP overhead, PCIe and storage limits. A single NVMe drive often becomes the bottleneck before the network does.
What is the difference between 1 Gbps and 1 GB/s?
A factor of 8. 1 Gbps is 125 MB/s while 1 GB/s is 1,000 MB/s, so 1 GB/s is eight times faster and corresponds to 8 Gbps. This is the most common unit confusion in storage and network specifications, because drive interfaces are often quoted in GB/s while network interfaces are quoted in Gbps.
How much real throughput can I expect from a 10 GbE link?
Between 1,100 and 1,180 MB/s for a single TCP stream on modern hardware. Reaching the full 1,250 MB/s requires jumbo frames, tuned TCP window sizes and hardware offload, and even then the theoretical figure is not attainable because Ethernet framing and the IP and TCP headers consume part of every packet.
Does this work for 100 Gbps links?
Yes — 100 Gbps × 125 = 12,500 MB/s, or 12.5 GB/s. The arithmetic scales linearly at every speed, so the same multiplier applies to 25, 40, 100 and 400 Gbps. Only the practical efficiency changes, and it tends to improve at higher speeds because packet-per-second limits matter less.