Audio duration calculator for many files at once
How long is this album, this audiobook, this folder of lectures or this batch of podcast episodes? This audio duration calculator reads the length of every audio file you drop on it and adds them up, with a per-file list you can sort and export as CSV. No uploading: the files are read on your device.
You can also type or paste a list of times — track lengths from a tracklist, an M3U playlist or notes — and it works as an audio time calculator, adding hours, minutes and seconds for you. Files and typed times are added together.
How to use the Total Audio Duration Calculator
- Drop your audio files on the box, or click it to choose them. Add more at any time.
- Optionally type or paste times, one per line, such as 3:45 or 1h 2m.
- Read the total, the average and the longest item. Choose a listening speed to see how long it takes at 1.5× or 2×.
- Sort the list by name or length, and press Download CSV for a spreadsheet with a total row.
Total Audio Duration Calculator features
Reads the real length
MP3 frames are counted, so variable-bitrate files are measured exactly rather than estimated from the bitrate.
Many formats
MP3, WAV, M4A/MP4, AAC, FLAC, Ogg Vorbis, Opus and AIFF from their headers; other formats your browser can play through its media player.
Typed times and playlists
h:mm:ss, m:ss, decimal seconds, “2 min 30 sec” and M3U #EXTINF lines.
Listening speed
See how long the total takes at 1.25×, 1.5×, 1.75× or 2×.
CSV export
Name, format, seconds, h:mm:ss, size and where the length was read from, plus the total.
Where each length comes from
Reading the headers is fast and exact, and works even for files the browser cannot play. The same tag engine powers the audio metadata viewer.
| Format | How the duration is read |
|---|---|
| MP3 | Every MPEG audio frame is counted: frames × samples per frame ÷ sample rate |
| WAV | Size of the data chunk ÷ bytes per second from the fmt chunk |
| FLAC | Total samples ÷ sample rate from the STREAMINFO block |
| Ogg Vorbis, Opus | Last granule position ÷ sample rate (Opus minus pre-skip) |
| M4A, MP4, AAC | Track duration in the mdhd box, or ADTS frames counted |
| AIFF | Sample frames ÷ sample rate from the COMM chunk |
| Others | Your browser’s media player (marked “browser” in the list) |
Worked example
The example list adds 0:45 + 12:30 + 1:04:10 + 1 h 2 min 3 s + 245 s (the M3U line) = 8,613 seconds, shown as 2:23:33: 143.6 minutes or 2.39 hours. At 2× it takes 1:11:47 to listen to.
To plan a podcast feed, the podcast RSS feed generator needs each episode’s length; to merge the files into one, use the audio joiner. For adding clock times rather than lengths, the time duration calculator is the better fit.
Tips for accurate totals
- Check the “Read from” column: “browser” rows come from your browser’s player and can be off by a fraction of a second for some formats.
- A row in red could not be read. It is left out of the total; convert or re-export that file and drop it again.
- Very large folders work, but the files are read one after another, so hundreds of long WAV files take a while.
- Sort by “Longest first” to find the episode or track that breaks a time limit.
Total Audio Duration Calculator FAQ
How do I find the total length of many audio files?
Drop them all on this audio duration calculator. Each file’s length is read from its header and the total appears at once, with a per-file list.
Are my files uploaded?
No. They are read in your browser and never leave your device, so large and private recordings are fine.
Why is the MP3 length different from my player?
Some players estimate the length from the bitrate, which is wrong for variable-bitrate files without a header. This tool counts the frames, which is exact to within one frame (about 26 ms).
Can I add up song lengths from a tracklist?
Yes. Paste the list with one time per line, for example “Track 1 – 3:45”. Lines without a time are ignored and counted.
How long does an audiobook take at 1.5× speed?
Choose 1.5× under Listening speed: the caption shows the total divided by 1.5.
Which formats work?
MP3, WAV, M4A, AAC, FLAC, OGG, Opus and AIFF are read directly. WMA, WebM and others work when your browser can play them.