DataCalc
Transfer Time Calculator
Media transfer time calculator for video professionals. Estimate file transfer times across different storage devices, connections, and network speeds.
How this calculator works
The Transfer Time calculator estimates how long it takes to copy media between drives, cards, and networks. Enter the amount of data and a connection or drive speed, and it returns a realistic transfer time — essential for planning offloads on set and shuttle-drive turnarounds in post.
Real-world transfers rarely hit an interface's advertised maximum: protocol overhead, drive limits, and many small files all slow things down. Plan with sustained real-world rates, not the number on the box.
Transfer time from size and speed
Time (s) = Data (GB) × 1,000 ÷ Speed (MB/s)
Example: 2 TB at a sustained 400 MB/s → 2,000 × 1,000 ÷ 400 = 5,000 s ≈ 1 h 23 min.
| Sustained speed | Typical of | Time for 1 TB |
|---|---|---|
| 100 MB/s | Spinning HDD, Gigabit Ethernet | ≈2 h 47 min |
| 250 MB/s | Fast HDD RAID, SATA SSD (slower) | ≈1 h 7 min |
| 500 MB/s | SATA SSD | ≈33 min |
| 1,000 MB/s | 10GbE, USB 3.2 Gen 2 NVMe | ≈17 min |
| 2,500 MB/s | Thunderbolt NVMe RAID | ≈7 min |
Sustained speeds are typically 60–80% of an interface's theoretical maximum.
Frequently asked questions
Why is my transfer slower than the advertised speed?
Interface ratings are theoretical bits-per-second maximums. Protocol overhead, the slower of the two drives, thermal throttling, and thousands-of-small-files workloads all reduce real throughput — 60–80% of the rated speed is a good planning number.
How long does it take to copy 1 TB over USB?
On USB 3.2 Gen 2 (10 Gb/s) with fast SSDs on both ends, roughly 17–25 minutes. Over older USB 3.0 with a spinning drive, closer to 3 hours. The drives usually matter more than the cable.
What is the fastest way to offload camera cards?
A fast card reader (CFexpress readers can exceed 1,000 MB/s) over Thunderbolt or USB 3.2 Gen 2, writing to an NVMe SSD or RAID. Checksummed offload tools add safety with some speed cost — budget for it.
Should I plan transfers with bits or bytes?
Network speeds are quoted in bits (10GbE = 10 gigabits/s ≈ 1,250 MB/s theoretical), drive speeds in bytes. This calculator accepts both units so you don't have to convert by hand.
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DataCalc is built by CONFORM.TOOLS — professional conform and post-production software for editors, assistant editors, and finishing artists. If DataCalc saves you time, take a look at what else we make.