Quick answer
Required bandwidth = data size × 8 ÷ time. Transferring 4.7 GB in 600 seconds needs 62.67 Mbps, or 7.83 MB/s.
Enter the data size, its unit and the time allowed. The calculator returns the bandwidth in Mbps and MB/s.
Related tools: Download Time Calculator: Time to download a file at a given speed. Data Transfer Calculator: Amount of data moved at a speed over a time. Media File Size Calculator: File size of an audio or video stream from its bitrate and duration.
How to use the Bandwidth Calculator
- Enter data size (above 0).
- Choose size unit: kB, MB, GB, TB, KiB and MiB and 2 more.
- Enter time allowed (s) (above 0).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| Data size | A number | > 0 |
| Size unit | Choose one: kB; MB; GB; TB; KiB; MiB; GiB; TiB | Starts at GB |
| Time allowed | A number, in s | > 0 |
Formula and method
Formula
bandwidth = size × 8 ÷ time
IEEE-754 double precision; shown to the decimals indicated.
Add headroom for protocol overhead.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: Data size = 4.7; Size unit = GB; Time allowed = 600.
| Result | Value |
|---|---|
| Bandwidth required | 62.6667 Mbps |
| In MB/s | 7.8333 |
Example 2
Inputs: Data size = 500; Size unit = MB; Time allowed = 30.
| Result | Value |
|---|---|
| Bandwidth required | 133.3333 Mbps |
| In MB/s | 16.6667 |
Example 3
Inputs: Data size = 2; Size unit = TB; Time allowed = 86400.
| Result | Value |
|---|---|
| Bandwidth required | 185.1852 Mbps |
| In MB/s | 23.1481 |
The first line is the headline result (bandwidth required). Below it the bandwidth Calculator lists in MB/s, which describe the same case from other angles. IEEE-754 double precision; shown to the decimals indicated.
The arithmetic
4.7 GB is 37,600 megabits; ÷ 600 s = 62.67 Mbps. A DVD (4.7 GB) in ten minutes therefore needs a connection of at least this speed.
Overhead
Protocol overhead, latency and shared links aren't included: real throughput is often 80 to 90% of the line rate, so add margin. Bits and bytes differ by a factor of 8.
How the result changes with data size
Holding every other input at the first worked example, this table changes only data size. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| Data size | Bandwidth required | In MB/s |
|---|---|---|
| 2.35 | 31.3333 Mbps | 3.9167 |
| 4.7 | 62.6667 Mbps | 7.8333 |
| 9.4 | 125.3333 Mbps | 15.6667 |
| 18.8 | 250.6667 Mbps | 31.3333 |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- Data size: entering "0" shows "Data size must be greater than 0." beside that field and no result.
- Time allowed: entering "0" shows "Time allowed must be greater than 0." beside that field and no result.
Choosing between the Bandwidth Calculator and similar calculators
Each row shows what a related calculator on this site asks for and what it returns, so you can pick the one that matches your question.
| Calculator | You enter | It returns |
|---|---|---|
| [Download Time Calculator](/technology/download-time-calculator/) | file size, size unit and connection speed | Time |
| [Data Transfer Calculator](/technology/data-transfer-calculator/) | speed, speed unit and duration | Data transferred |
| [Media File Size Calculator](/technology/file-size-calculator/) | bitrate, bitrate unit and hours | File size |
| [Bitrate Calculator](/technology/bitrate-calculator/) | file size, size unit and duration | Average bitrate |
| [Upload Time Calculator](/technology/upload-time-calculator/) | file size, size unit and connection speed | Time |
Background: networking and display
Network speeds are quoted in bits per second and file sizes in bytes, and a byte is 8 bits, so a 100 Mbps link moves at most 12.5 megabytes per second; real throughput is usually below the advertised rate. Pixel density is the diagonal in pixels divided by the diagonal in inches: a 1920×1080 display of 24 inches is about 92 pixels per inch, and a 3840×2160 display of 27 inches about 163.
Assumptions and limitations
- Overhead is not included
If a required value is empty, not a number, or outside its allowed range, the form marks that field with a message and shows no result instead of a misleading number. The automated checks deliberately try invalid entries for data size and time allowed to confirm this.
Frequently asked questions
How long does 1 GB take at 100 Mbps?
1 GB is 8,000 Mbit, so at 100 Mbps it takes about 80 seconds in ideal conditions.
What is Mbps?
Megabits per second.
How do I allow for overhead?
Add about 10 to 20%.
What does the Bandwidth Calculator calculate?
Bandwidth needed to move a file in a given time. It returns Bandwidth required and In MB/s.
What formula does the Bandwidth Calculator use?
bandwidth = size × 8 ÷ time. Add headroom for protocol overhead.
What do I need to enter in the bandwidth Calculator?
You enter Data size, Size unit and Time allowed (s).
How is the result rounded or limited?
IEEE-754 double precision; shown to the decimals indicated. Overhead is not included.
What does the “Size unit” option change?
It sets how the bandwidth is worked out. The choices are kB, MB, GB, TB, KiB, MiB, GiB and TiB.
What is an example of a bandwidth result?
With data size 4.7, size unit GB and time allowed 600, the bandwidth required is 62.6667 Mbps.
Related calculators
- Download Time Calculator — Time to download a file at a given speed.
- Data Transfer Calculator — Amount of data moved at a speed over a time.
- Media File Size Calculator — File size of an audio or video stream from its bitrate and duration.
- Bitrate Calculator — Average bitrate of a file from its size and duration.
- Upload Time Calculator — Time to upload a file at a given speed.
- IP Subnet Calculator — IPv4 network, broadcast, mask and host range from an address and CIDR prefix.
- Latency to Distance Calculator — Approximate one-way distance from round-trip latency.
- Network Throughput Calculator — Maximum TCP throughput from window size and round-trip time.
Sources
- SI prefixes (kB = 1,000 B) and IEC prefixes (KiB = 1,024 B); 8 bits per byte
Content last reviewed 2026-11-04. Formulas and worked examples are checked by automated tests against independently computed values.