Data Transfer Time Calculator
See how many days your data takes to transfer, and the bandwidth you need to hit your deadline.
Each one fills in the fields below for a typical workload of that kind. You can change any of them.
Optional
- Deadline
- At risk, 26 days late
- Link speed for the deadline
- 1.4 Gbps
- Moves a day
- 5.2 TB
450 TB at an effective 644 Mbps.
What this means
- Deadline at risk
At 1 Gbps and 18 hours a day this takes about 86 days; your deadline is 60 days away. Meeting it needs about 1.4 Gbps at the same usable share and hours.
- Offline transfer candidate
450 TB is large for this link. A transfer appliance or terminal usually reaches the cloud in two to five weeks whatever the link speed. Compare both in the transfer cost comparator.
- The daily window is a lever
Running the copy 24 hours a day instead of 18 would finish in about 65 days, 22 days sooner.
What this model assumes
Show
- The formula is AWS’s. Days = data in bits / (link bits a second x usable share x 3,600 x hours a day). AWS calls it a theoretical minimum; 100 TB on 1 Gbps at 80% all day is 11.57 days.
- Decimal units. 1 TB is 1012 bytes and 1 Gbps is 109 bits a second, as storage arrays and carriers count them.
- Protocol efficiency defaults to 92%. TCP, IP and TLS framing and the transfer tool’s own protocol take the rest. Measure a pilot copy and set the figure you see.
- Small files are a band, not a curve. Average files of 8 to 64 MB run at 90% of the rate, 1 to 8 MB at 75%, 128 KB to 1 MB at 50% and smaller at 30%. These are rules of thumb; a pilot is the real measure.
- Not counted: source storage that cannot read as fast as the link, outages, and pauses between waves. Leave room for them in the deadline.
Planning the target architecture?
Cloud Cost Audit: We review placement, network design and egress before the first bill arrives, so the migration does not carry avoidable transfer costs into the cloud. From $1,500, fixed. Nothing paid upfront.
Questions
How long does it take to transfer 100 TB over a 1 Gbps link?
About 9.3 days if the whole link ran flat out all day, which no transfer does. At 80% of the link, 24 hours a day, AWS's formula gives 11.6 days, and after protocol overhead expect about 12.6. At 70% for 18 hours a day it is about 19 days.
How do you calculate data transfer time?
Divide the data in bits by the bits a second you can actually use. AWS publishes it as: days = bytes x 8 / (link bits a second x usable share x 3,600 x hours a day). Then allow for protocol overhead, small files and storage that cannot read as fast as the link.
What bandwidth do I need to migrate by a deadline?
Enter the deadline and the page works backwards: the link speed that moves your data in that many days at the same usable share, hours and losses. If it is more than twice what you have, an offline transfer is usually worth pricing.
When should I ship data on an appliance instead?
When the online copy takes more than about a month, or the deadline needs more than double your link. An appliance or the AWS Data Transfer Terminal usually lands data in two to five weeks whatever the link speed. The transfer cost comparator prices both.
Why do small files make a transfer slower?
Every file costs a round trip to open, write metadata and confirm, on top of its bytes. Millions of files under 1 MB can halve the effective rate or worse, and in object storage each file is also a billed request.
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OpenMore tools for: Network and data transfer
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Once the data is in the cloud, Finitizer puts every data transfer line next to the workload causing it, across accounts and projects, so placement mistakes show up in the first month.
See how Finitizer works