Quick answer
Average bitrate = file size × 8 ÷ duration. A 700 MB file of 5,400 seconds (90 minutes) has an average bitrate of 1,037.04 kbps.
Enter the file size, its unit and the duration in seconds. The calculator returns the average bitrate.
Related tools: Media File Size Calculator: File size of an audio or video stream from its bitrate and duration. Data Transfer Calculator: Amount of data moved at a speed over a time. Download Time Calculator: Time to download a file at a given speed.
How to use the Bitrate Calculator
- Enter file size (above 0).
- Choose size unit: kB, MB, GB, TB, KiB and MiB and 2 more.
- Enter duration (s) (above 0).
- Press Calculate to see the result, and use Reset to start again.
| Input | What to enter | Allowed values |
|---|---|---|
| File size | A number | > 0 |
| Size unit | Choose one: kB; MB; GB; TB; KiB; MiB; GiB; TiB | Starts at MB |
| Duration | A number, in s | > 0 |
Formula and method
Formula
bitrate = size × 8 ÷ duration
IEEE-754 double precision; shown to the decimals indicated.
Includes container overhead.
Worked examples
These examples are verified: each one is an automated test case that the live calculator must reproduce exactly.
Example 1
Inputs: File size = 700; Size unit = MB; Duration = 5400.
| Result | Value |
|---|---|
| Average bitrate | 1,037.04 kbps |
Example 2
Inputs: File size = 50; Size unit = MB; Duration = 240.
| Result | Value |
|---|---|
| Average bitrate | 1,666.67 kbps |
The first line is the headline result (average bitrate). IEEE-754 double precision; shown to the decimals indicated.
The arithmetic
700 MB = 5,600 megabits; ÷ 5,400 s = 1.037 Mbps. A 1 GB file of 90 minutes would be about 1.5 Mbps. The result is the average, not the instantaneous bitrate, which varies in VBR files.
Use
Estimate whether a connection can stream a file or what compression a video needs for a given size. Audio and video bitrates combine: add the audio's 128 kbps to see the total.
How the result changes with file size
Holding every other input at the first worked example, this table changes only file size. It shows how sensitive the answer is to that one value; each row was produced by running this calculator.
| File size | Average bitrate |
|---|---|
| 350 | 518.52 kbps |
| 700 | 1,037.04 kbps |
| 1400 | 2,074.07 kbps |
| 2800 | 4,148.15 kbps |
What happens with invalid input
These messages are produced by the calculator itself, so you know what to fix.
- File size: entering "0" shows "File size must be greater than 0." beside that field and no result.
- Duration: entering "0" shows "Duration must be greater than 0." beside that field and no result.
Choosing between the Bitrate 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 |
|---|---|---|
| [Media File Size Calculator](/technology/file-size-calculator/) | bitrate, bitrate unit and hours | File size |
| [Data Transfer Calculator](/technology/data-transfer-calculator/) | speed, speed unit and duration | Data transferred |
| [Download Time Calculator](/technology/download-time-calculator/) | file size, size unit and connection speed | Time |
| [Bandwidth Calculator](/technology/bandwidth-calculator/) | data size, size unit and time allowed | Bandwidth required |
| [Audio File Size Calculator](/technology/audio-file-size-calculator/) | bitrate and duration | File size |
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
- Average, not instantaneous
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 file size and duration to confirm this.
Frequently asked questions
What bitrate is 1080p streaming?
1080p streaming usually runs at about 3 to 8 Mbps, depending on the codec and service.
How do I get size from bitrate?
Size = bitrate × time ÷ 8: 5,000 kbps for 600 s is 375,000 kB.
Is the size decimal or binary?
This page uses decimal megabytes (1 MB = 1,000,000 bytes); binary MiB would be about 4.6% smaller.
What does the Bitrate Calculator calculate?
Average bitrate of a file from its size and duration. It returns Average bitrate.
What formula does the Bitrate Calculator use?
bitrate = size × 8 ÷ duration. Includes container overhead.
What do I need to enter in the bitrate Calculator?
You enter File size, Size unit and Duration (s).
How is the result rounded or limited?
IEEE-754 double precision; shown to the decimals indicated. Average, not instantaneous.
What does the “Size unit” option change?
It sets how the bitrate is worked out. The choices are kB, MB, GB, TB, KiB, MiB, GiB and TiB.
What is an example of a bitrate result?
With file size 700, size unit MB and duration 5400, the average bitrate is 1,037.04 kbps.
Related calculators
- Media File Size Calculator — File size of an audio or video stream from its bitrate and duration.
- Data Transfer Calculator — Amount of data moved at a speed over a time.
- Download Time Calculator — Time to download a file at a given speed.
- Bandwidth Calculator — Bandwidth needed to move a file in a given time.
- Audio File Size Calculator — File size of audio at a constant bitrate.
- Video File Size Calculator — File size of video with audio at constant bitrates.
- Playback Speed Calculator — New duration and time saved at a faster playback speed.
- Binary Calculator — Add, subtract, multiply, divide or apply bitwise operations to binary numbers.
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.