Mbps to Gbps Converter
Convert megabits per second to gigabits per second and back for internet plans, speed tests and Ethernet ports, with the matching MB/s a download manager shows and a download-time calculator.
1 Gbps = 1,000 Mbps · 1 Mbps = 0.001 Gbps
Why It Is Always 1,000, Never 1,024
Data rates use the ordinary SI prefixes: mega is a million and giga is a billion, so a gigabit per second is exactly 1,000 megabits per second. The 1,024 factor belongs to memory and file sizes in some operating systems. It never applies to line rates. Ethernet, Wi-Fi, USB, DOCSIS cable and fibre standards all define speeds in powers of ten, and internet providers advertise them the same way.
So 850 Mbps is 0.85 Gbps, and a 2.5 Gbps port is 2,500 Mbps. Move the decimal point three places.
Internet Plan Speeds in Mbps, Gbps and MB/s
Common advertised tiers. The last column is the most real data a wired connection can move after Ethernet and TCP overhead, which is what Steam, a browser or a file-copy dialog reports.
| Mbps | Gbps | MB/s (÷8) | Real MB/s, wired |
|---|---|---|---|
| 25 Mbps | 0.025 | 3.1 | ≈ 3 |
| 100 Mbps | 0.1 | 12.5 | ≈ 12 |
| 300 Mbps | 0.3 | 37.5 | ≈ 35 |
| 500 Mbps | 0.5 | 62.5 | ≈ 59 |
| 940 Mbps | 0.94 | 117.5 | ≈ 111 |
| 1,000 Mbps | 1 | 125 | ≈ 118 |
| 1,200 Mbps | 1.2 | 150 | ≈ 141 |
| 2,000 Mbps | 2 | 250 | ≈ 235 |
| 2,500 Mbps | 2.5 | 312.5 | ≈ 294 |
| 5,000 Mbps | 5 | 625 | ≈ 588 |
| 8,000 Mbps | 8 | 1,000 | ≈ 941 |
| 10,000 Mbps | 10 | 1,250 | ≈ 1,177 |
Port and Cable Speeds Compared
Hardware is usually rated in Gbps and plans in Mbps, which makes it easy to miss that a port can't carry the plan you're paying for. These are the signalling rates in each standard. Real transfers are lower, especially on Wi-Fi.
| Interface | Mbps | Gbps | Where you see it |
|---|---|---|---|
| USB 2.0 Hi-Speed | 480 | 0.48 | Older flash drives, cheap Ethernet adapters |
| Fast Ethernet (100BASE-TX) | 100 | 0.1 | Old routers, smart TVs, damaged cables |
| Gigabit Ethernet (1000BASE-T) | 1,000 | 1 | Most router and PC ports |
| Wi-Fi 5, 2 streams, 80 MHz | 867 | 0.867 | Link rate shown in OS, not throughput |
| Wi-Fi 6, 2 streams, 160 MHz | 2,402 | 2.402 | Link rate; real transfers are far lower |
| 2.5GBASE-T | 2,500 | 2.5 | Newer routers, gaming boards, multi-gig plans |
| USB 3.2 Gen 1 (“USB 5Gbps”) | 5,000 | 5 | Portable SSDs, USB-C docks |
| SATA III | 6,000 | 6 | Internal 2.5″ SSDs and hard drives |
| 10GBASE-T / SFP+ | 10,000 | 10 | 10 Gbps plans, NAS, office switches |
| Thunderbolt 4 / USB4 40Gbps | 40,000 | 40 | Docks, external NVMe enclosures |
Why a 1 Gbps Plan Tests at About 940 Mbps
A gigabit Ethernet port sends 1,000 Mbps of raw signal, but some of it is packaging. Every packet has a preamble, Ethernet header, checksum and a mandatory gap before the next one, plus IP and TCP headers inside. Speed tests measure only the data that arrives, so they can never show the full 1,000.
Step 1: Bytes on the wire for one full-size packet
Step 2: Bytes of your data inside it
Step 3: Share of the line rate
So 930–945 Mbps on a gigabit plan is a perfect result, not a fault. Some providers provision a little above the advertised rate so that customers still see the plan figure after overhead, but a 1 Gbps Ethernet port can't pass more than about 941 Mbps of data whatever the plan. The same ~94% rule applies at every tier: a 2.5 Gbps port tops out near 2,350 Mbps.
Download Time Calculator
File sizes are in bytes and speeds in bits, so multiply the size by 8 before dividing. This does it for you, in Mbps or Gbps.
- At the full line rate
- 26 min 40 s
- Realistic best case (~94%)
- 28 min 19 s
800,000 megabits ÷ 500 Mbps. Sizes use decimal units (1 GB = 1,000 MB), as game stores and drive makers do.
Worked Example: a 100 GB Game on 500 Mbps
A game store lists a 100 GB install. Your plan is 500 Mbps. How long, and how does it compare with upgrading to 2 Gbps?
Step 1: Gigabytes to megabits
Step 2: Divide by the speed
Step 3: The 2 Gbps option
The upgrade only pays off if everything in the path is multi-gig. Plugged into a normal gigabit port, the 2 Gbps plan is capped near 941 Mbps, so the download takes about 14 minutes, not 7. Game servers and the drive writing the files can also be the limit.
The Slowest Link Sets Your Speed
Converting everything to the same unit is the quickest way to find a bottleneck. Line up each hop from the provider to your device in Mbps and the smallest number is your ceiling:
- Exactly ~94 Mbps on a fast plan almost always means something negotiated Fast Ethernet (100 Mbps): a cable with a broken pair, an old switch, or a 100 Mbps port on a TV or console. Check the link speed in the network adapter's status.
- Stuck near 300–400 Mbps is common with USB 2.0 Ethernet adapters, which share a 480 Mbps bus.
- A multi-gig plan stuck at 940 Mbps means a 1 Gbps port somewhere: the router's LAN port, a switch, or the computer's network card.
- Wi-Fi link rates (the “2,402 Mbps” a laptop reports) are radio signalling rates. Usable throughput is typically half or less, and it falls with distance and walls.
What Counts as “Broadband” in Mbps
In March 2024 the US Federal Communications Commission raised its fixed-broadband benchmark from 25/3 Mbps to 100 Mbps download and 20 Mbps upload, and set a long-term goal of 1 Gbps down and 500 Mbps up (1,000/500 Mbps). Since 2024, US providers must also show a standard “Broadband Facts” label listing typical download and upload speeds in Mbps, which makes plans easier to compare in a single unit.
When comparing, match download with download and upload with upload. Cable plans are often asymmetric (for example 1,000 Mbps down, 35 Mbps up), while fibre plans are frequently symmetric, so the upload figure can differ by a factor of 20 or more between plans with the same headline speed.
Frequently asked questions
Is 1 Gbps faster than 500 Mbps?
Yes, twice as fast. 1 Gbps is 1,000 Mbps. The different units can make 500 look like the bigger number at a glance.
How many MB/s is 1 Gbps?
125 MB/s in theory (1,000 ÷ 8). After Ethernet and TCP overhead, a wired download peaks at about 117 MB/s.
Is 0.1 Gbps the same as 100 Mbps?
Yes. Multiply by 1,000: 0.1 × 1,000 = 100 Mbps, the old Fast Ethernet speed.
Do I need a new router for a 2 Gbps plan?
Usually. To see more than about 940 Mbps on one device, the router WAN port, the LAN port, any switch and the device itself all need 2.5 Gbps or faster ports.
Sources
- NIST: SI prefixes: mega = 10⁶ and giga = 10⁹, the factors used for data rates.
- IEEE 802.3 Ethernet standard: frame format, preamble and inter-packet gap used in the 941 Mbps calculation.
- FCC: Broadband speed benchmark increased to 100/20 Mbps (2024): the benchmark and the 1 Gbps/500 Mbps long-term goal.
- FCC: Broadband consumer labels: the Broadband Facts label with typical speeds in Mbps.
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