File Transfer Time Calculator for LAN, USB & NAS
Enter the data size and a realistic sustained rate for the slowest part of the path. The estimate works for LAN copies, NAS migrations, USB drives, SSDs, and remote transfers.
That is the ideal decimal-unit time. A 1 Gbps link does not guarantee a 1 Gbps file payload: storage, Wi-Fi, protocol overhead, encryption, and small-file work can all become the bottleneck.
Enter your values
100 GB at 50 Mbps
- Total seconds
- 16,000
- Calculation model
- Decimal units, ideal sustained rate
Nothing is uploaded. Results update locally as you type.
How it works
Transparent math, not a mystery result.
NetCalcKit uses standard decimal network units unless the page explicitly says otherwise. The calculator updates in your browser and labels ideal estimates separately from real-world conditions.
Quick reference
File transfer time across common sustained rates
These times use decimal file sizes and payload rates. Enter a measured sustained rate when possible; a port label or peak benchmark can be much faster than a complete copy job.
| Data size | 100 Mbps | 1 Gbps | 100 MB/s | 500 MB/s |
|---|---|---|---|---|
| 1 GB | 1 min 20 sec | 8 sec | 10 sec | 2 sec |
| 10 GB | 13 min 20 sec | 1 min 20 sec | 1 min 40 sec | 20 sec |
| 100 GB | 2 hr 13 min 20 sec | 13 min 20 sec | 16 min 40 sec | 3 min 20 sec |
| 500 GB | 11 hr 6 min 40 sec | 1 hr 6 min 40 sec | 1 hr 23 min 20 sec | 16 min 40 sec |
| 1 TB | 22 hr 13 min 20 sec | 2 hr 13 min 20 sec | 2 hr 46 min 40 sec | 33 min 20 sec |
Choose a realistic rate
The slowest part of the path sets the copy speed
A transfer can involve source storage, a cable or Wi-Fi link, switches, a NAS, encryption, a file-sharing protocol, destination storage, and CPU work. The job cannot sustain a rate above its active bottleneck.
For a repeatable workflow, time an earlier transfer with similar file sizes and use its average payload rate. If no measurement exists, use the most conservative sustained specification in the path rather than the fastest interface label.
- A USB 3 port does not make a slow hard drive write at USB 3’s maximum rate.
- A gigabit NAS copy can be limited by 2.4 GHz Wi-Fi before Ethernet matters.
- Encryption or compression may make CPU the bottleneck.
- An SSD cache can make the beginning of a write look faster than the full job.
- Many small files add metadata and per-file work that one large file avoids.
Migration examples
Four transfer estimates you can check
Each figure is an ideal baseline using the stated sustained payload rate, not the advertised maximum of an interface.
100 GB to a NAS at 80 MB/s
20 min 50 secPermission checks, small files, antivirus, and NAS disk writes can extend the copy.
500 GB over 1 Gbps Ethernet
1 hr 6 min 40 secThis requires the full mathematical link rate; a real SMB copy will usually take longer.
1 TB external drive copy at 150 MB/s
1 hr 51 min 7 secA hard drive may slow across the disk or during small-file workloads.
50 GB over 100 Mbps Wi-Fi payload
1 hr 6 min 40 secUse measured payload speed rather than the much larger Wi-Fi link-rate label.
Before scheduling downtime
Common file-transfer planning mistakes
A migration window should include the copy plus any preparation and verification that happens outside the transfer formula.
- Using interface maximums instead of sustained end-to-end payload speed.
- Entering Mbps as MB/s and making the result eight times too fast.
- Ignoring a slower source disk, destination disk, Wi-Fi link, CPU, or remote service.
- Using one large-file benchmark for a directory containing millions of small files.
- Leaving out scan, archive, encryption, checksum, index, and restore-verification time.
- Assuming decimal TB and binary TiB contain the same number of bytes.
Continue with confidence
Related tools and practical guides
File Transfer Bottlenecks
Diagnose storage, network, protocol, CPU, and small-file limits.
Open page ↗MB/s to Mbps Converter
Compare an observed copy speed with a network link rate.
Open page ↗Download Time Calculator
Estimate a public internet download with server and Wi-Fi context.
Open page ↗Upload Time Calculator
Plan cloud and video uploads using upstream capacity.
Open page ↗Calculation Methodology
Check unit conventions and ideal-rate assumptions before planning a migration.
Open page ↗What this tool answers
Plan local and remote transfers across Ethernet, Wi-Fi, USB, NAS, or storage by comparing file size with a realistic sustained transfer rate.
Common questions
Good to know.
How long does 100 GB take over gigabit Ethernet?+
The ideal time at exactly 1 Gbps is 13 minutes 20 seconds. A practical file copy often takes longer because usable throughput is below the link rate and storage must keep up.
Can I use MB/s from a disk benchmark?+
Yes, but use a sustained result that resembles the real workload. A short sequential benchmark can be much faster than a long copy, mixed files, or a nearly full drive.
Why are many small files slower than one large file?+
Each file can require metadata lookups, permission checks, open and close operations, directory updates, antivirus scanning, and separate network requests.
Which speed should I enter for a NAS transfer?+
Use the lowest realistic sustained rate among the source storage, destination storage, network link, Wi-Fi path, and protocol. A measured previous copy is often the best input.
Does the estimate include verification or checksum time?+
No. It estimates the transfer itself. Source scanning, archive creation, encryption, checksum verification, indexing, and post-copy validation can add separate time.
Understand the result
Helpful guides for this calculator
Calculate Download Time
Learn the download-time formula with worked 1 GB, 10 GB and 100 GB examples. Convert Mbps or MB/s correctly and account for real-world slowdowns.
9 min read · Read guide ↗Guide 05File Transfer Bottlenecks
Diagnose slow LAN, NAS and USB copies using sustained speed, storage activity and file count. Work through a 100 GB example before replacing any hardware.
10 min read · Read guide ↗Guide 10Download Time Chart
Compare 100 MB to 200 GB download times at 10 Mbps through 1 Gbps. Read the chart correctly, then plan clearly with your measured sustained speed.
9 min read · Read guide ↗