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Transferring 100 GB over USB 3.0 takes 2m 40s

A 100 GB transfer over USB 3.0 works out to exactly 2 minutes 40 seconds at the interface's 5 Gbps peak rate. That's the physics — the number you'd see if both ends sustained the full 5000 Mbps with no protocol overhead and no disk bottleneck.

Transfer time
2m 40s
At peak link speed
File size
100 GB
100 GB
Link speed
5,000 Mbps
USB 3.0 (5 Gbps)

Calculator

Data Transfer Calculator

Configuration

Mbps
Estimated Transfer Time
2m 40s

Speed Comparison

USB 2.0
27m 46s
480 Mbps
USB 4 / Thunderbolt 4
20s
40 Gbps
Gigabit Ethernet
13m 20s
1 Gbps
10 Gigabit Ethernet
1m 20s
10 Gbps
WiFi 5 (ac)
33m 20s
400 Mbps
WiFi 7 (be)
2m 40s
5 Gbps
SATA SSD
3m 1s
4.4 Gbps
NVMe Gen4 SSD
14s
56 Gbps

How this is calculated

Real-world USB 3.0 transfers rarely hit the calculated peak. External SATA-based drives usually top out around 4400 Mbps (~550 MB/s), which slows 100 GB to about 3 minutes. Portable HDDs get much worse — around 100–120 MB/s sustained, or 11–13 minutes for the same file. The calculator's number is the floor; the drive is almost always the actual bottleneck, not the USB link.

Verdict

2m 40s is the absolute best case for 100 GB over USB 3.0. Plan for 3–5 minutes with an SSD, or 10+ minutes with a spinning disk. The cable is rarely the issue at this data rate.

More USB scenarios

1 TB over USB 3.0
USB 3.0 (5 Gbps)
View details ➜
4 GB over USB 2.0
USB 2.0 (480 Mbps)
View details ➜

Frequently asked questions

How long does it take to transfer 1 TB over Gigabit Ethernet?
At a theoretical 1000 Mbps (125 MB/s), 1 TB takes about 2 hours and 13 minutes in ideal conditions. Real-world speeds over Gigabit Ethernet typically top out around 110-115 MB/s due to TCP overhead, so budget closer to 2.5 hours for a full 1 TB copy.
Why is my real transfer speed slower than the cable's rated speed?
Rated speeds are raw signalling rates in bits per second. Protocol overhead (TCP/IP, USB framing, filesystem operations), encryption, small-file latency, and the slowest device in the chain (often the disk, not the cable) all reduce usable throughput. A USB 3.0 port rated 5 Gbps usually delivers around 400 MB/s in practice, not the theoretical 625 MB/s.
What's the difference between megabits (Mbps) and megabytes (MB/s)?
There are 8 bits in a byte, so 1000 Mbps equals 125 MB/s. Network speeds and ISP plans are advertised in megabits per second, while file sizes and storage speeds are measured in megabytes per second. Dividing Mbps by 8 gives you the MB/s figure you actually see when copying files.
How fast is WiFi 6 compared to Gigabit Ethernet for file transfers?
WiFi 6 can exceed Gigabit Ethernet on paper (up to ~9.6 Gbps theoretical) but real-world throughput usually lands between 500 Mbps and 1.5 Gbps depending on distance, interference, and client hardware. For a single large file transfer, wired Gigabit is still more consistent; WiFi 6E or WiFi 7 can edge ahead in ideal conditions.
Is USB 4 or Thunderbolt 4 faster for copying files?
Both use the same 40 Gbps underlying spec and deliver comparable real-world speeds of around 2800-3200 MB/s for sustained transfers. Thunderbolt 4 guarantees the full 40 Gbps and PCIe 32 Gbps tunnel; USB 4 allows 20 Gbps implementations, so check the port's actual spec rather than assuming parity.
Does file size affect transfer speed?
Yes — significantly. Transferring one 50 GB file hits near-maximum throughput, but copying 50 GB of small files (thousands of photos, say) can be 5-10x slower because every file has filesystem and metadata overhead. For large migrations, compressing into an archive first is often faster end to end.

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