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Data Transfer Calculator

Estimate transfer times for files over USB, WiFi, Ethernet, and more.

Configuration

Mbps
Estimated Transfer Time
6m 40s

Speed Comparison

USB 2.0
13m 53s
480 Mbps
USB 4 / Thunderbolt 4
10s
40 Gbps
Gigabit Ethernet
6m 40s
1 Gbps
Selected
10 Gigabit Ethernet
40s
10 Gbps
WiFi 5 (ac)
16m 40s
400 Mbps
WiFi 7 (be)
1m 20s
5 Gbps
SATA SSD
1m 30s
4.4 Gbps
NVMe Gen4 SSD
7s
56 Gbps

About this tool

The Data Transfer Calculator estimates how long it will take to copy a file of any size across any interface, including USB 2.0 through USB 4, Thunderbolt, Gigabit and 10-Gigabit Ethernet, WiFi 5/6/7, SATA SSDs, or NVMe Gen4 drives. Pick a preset or punch in your own Mbps figure, enter the file size in MB, GB, or TB, and the tool returns a realistic transfer time broken down into days, hours, minutes, and seconds.

It's the quickest way to reality-check a backup plan, decide whether that external SSD is worth the money, or work out if you can finish a 200 GB game download before bed. Switch on Compare mode to put two connections head-to-head and see exactly how many minutes (or hours) you'd save by upgrading from WiFi to Ethernet, or from USB 3.0 to USB 4.

Formula

Transfer time is file size in bits divided by link speed in bits per second. The calculator converts your input to bits (1 byte = 8 bits, 1 GB = 8,000,000,000 bits using the decimal/SI convention drives are sold under), then divides by the Mbps figure times 1,000,000. Real-world overhead, such as TCP, USB framing, and filesystem operations, isn't modelled, so treat the result as an optimistic floor.

When to use it

Use it before buying storage or networking gear to see whether the spec jump is worth the price, when planning a big one-off copy like a photo-library migration, or when deciding between wired and wireless for a specific workload. Pair it with the RAID Calculator when sizing a NAS and the Display Bandwidth Calculator if you're comparing video cable throughput against the same numbers.

Popular transfer scenarios

Pre-computed copy times for the file-size + interface combinations visitors ask about most.

1 TB over USB 3.0
The baseline external-SSD transfer
View details ➜
1 TB over Thunderbolt 4
40 Gbps enclosure territory
View details ➜
1 TB over Gigabit Ethernet
The NAS-over-wire baseline
View details ➜
10 TB over 10 GbE
Home-lab scale migrations
View details ➜
100 GB over Wi-Fi 6
Realistic wireless copy times
View details ➜
100 GB over NVMe Gen 4
Internal-drive upper bound
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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