The recording length from file size calculates the length of a recording from its file size and bitrate. A 100 MB file at 128 kbps lasts 01:44:10. It is useful when you have a file and want to know roughly how long it plays before you open it.
Turn a recording into text
Drop an audio or video file, or a voice message, into the chat with @potok_now_bot; the recognized text is sent back there.
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Files up to 2 GB · export to TXT, MD, DOCX, PDF, SRT and VTT · speaker labels and timestamps · about 30 languages
Key facts
- Formula: seconds = size in bytes × 8 ÷ (kbps × 1000), applied to the numbers in the table below.
- Assumption: the bitrate is constant and 1 MB is 1,000,000 bytes.
- Take the bitrate from the file properties, not from memory.
- The values on this page are calculated in advance, not measured on a recording.
Calculation and example
Formula: seconds = size in bytes × 8 ÷ (kbps × 1000)
| Size (MB) | Bitrate (kbps) | Length (h:mm:ss) |
|---|---|---|
| 50 | 128 | 00:52:05 |
| 100 | 128 | 01:44:10 |
| 100 | 64 | 03:28:20 |
| 500 | 320 | 03:28:20 |
| 1500 | 128 | 26:02:30 |
A 100 MB file at 128 kbps lasts 01:44:10.
| Topic | Answer |
|---|---|
| Recognition | About 30 languages with good published results and a few more with warnings |
| Digest | The result message has a summary button for a digest of the text |
| Where to use it | The Telegram bot @potok_now_bot, plus its mini app for big uploads |
| Labels and times | Speaker labels and timestamps can be switched on |
| Save as | TXT, MD, DOCX, PDF, SRT, VTT |
From the table to your numbers
Start from the row that looks most like your situation. Change the numbers one by one, keep the formula as it is, and compare the new result with the row you started from. A result far from every row is a reason to check the inputs.
More
Terms used here are explained in the glossary. Handy helpers live in tools; apps are on the download page.
Common questions
How does the recording length from file size work?
It applies one rule: seconds = size in bytes × 8 ÷ (kbps × 1000). A 100 MB file at 128 kbps lasts 01:44:10.
What does the recording length from file size assume?
It assumes that the bitrate is constant and 1 MB is 1,000,000 bytes. When the conditions differ, recalculate with your values by the same formula.
What does the table of the recording length from file size show?
It shows: Size (MB), Bitrate (kbps), Length (h:mm:ss). Values: 50 | 128 | 00:52:05; 100 | 128 | 01:44:10; 100 | 64 | 03:28:20; 500 | 320 | 03:28:20; 1500 | 128 | 26:02:30.
Where do the definitions behind the recording length from file size come from?
Units, formats and rules are described in the sources listed at the bottom of this page. The numbers in the table are calculated here by the formula above and are not copied from those sources.
How do I avoid a mistake with the recording length from file size?
Take the bitrate from the file properties, not from memory. Use it when you have a file and want to know roughly how long it plays before you open it.
Sources
Each source was opened by hand on the date shown. Pages change, so open the source if a detail matters to you.
- Bit rate (Wikipedia), Wikipedia · checked
- Megabyte (Wikipedia), Wikipedia · checked
See the result on your recording
Drop an audio or video file, or a voice message, into the chat with @potok_now_bot; the recognized text is sent back there.
Open @potok_now_bot in Telegram