Check lengths.
Plan speaking time.
Drop in audio files to see each one's length, running total, and whether it fits the free transcriber — or paste a script to estimate how long it takes to say out loud. Nothing leaves your browser, no signup.
Duration calculator
No files added yet.
Checking local library…
Add audio files or pick recordings from your local library to check their lengths.
| File | Duration | Size | Running total | Fits transcription? | Actions |
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Add audio files or pick recordings from your local library to check their lengths.
Paste or drop a script to estimate speaking time. Nothing is uploaded.
Checking a length shouldn't require an upload
Most online duration tools work by uploading your file to a server just to read one number back. This one reads that number from the file itself, right in your browser tab, and never sends the file anywhere.
Files never leave your browser
Durations are read from local file metadata (or a local decode, if needed) — never a network call.
Scripts stay on your screen
Pasted or dropped text is analyzed in this tab and never transmitted, saved, or logged anywhere.
Instant, even on long files
Metadata reads are near-instant, so checking a two-hour recording is as fast as a two-minute one.
Two calculators, one tool
Check what you already have recorded, or plan what you're about to record. Either way the numbers update instantly as you work.
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Add your files or your script
Drop audio files, pick saved recordings from your library, or paste a script or transcript.
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Read the numbers
Per-file durations and a running total, or word/character/sentence counts — all live.
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Check the fit
See which clips fit the free 10-minute transcriber, or dial in a speaking pace for your script.
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Copy or move on
Copy a plain-text summary, or jump straight to the splitter, merger, or transcriber.
A few reasons people check durations
Sorting recordings before transcription
Drop a folder's worth of voice memos in and see at a glance which ones fit the free transcribe tool's 10-minute cap and which ones need a trip through the audio splitter first.
Planning a voiceover or podcast segment
Paste a script and get an honest estimate of how long it runs at your delivery pace, pauses included, before you ever hit record.
Budgeting a recording session
Add every take you're considering and watch the running total climb, so you know exactly how much material you have before you start editing.
Timing subtitles and transcripts
Drop an SRT or VTT file straight in — cue numbers and timestamps are stripped automatically, leaving just the words to count and time.
Record, trim, split, merge, and transcribe too — all local
Need a take before you check its length? Use the free voice recorder. Have a file that's over the 10-minute mark? Try the audio splitter or the audio trimmer to cut it down, or the audio merger to combine several short clips. Once a clip fits, the transcribe tool turns it into text — still no upload.
Audio duration calculator FAQ
Does this upload my audio files or script?
No. Audio durations are read locally with the browser's media APIs (or, on the rare file that needs it, a local decode) and script text stays in this tab. Nothing is sent to a server at any point.
How do you get a file's length without decoding the whole thing?
For most files the browser can report duration from the file's metadata almost instantly, even for a two-hour recording. A handful of encodes (some webm/opus streams) report an unusable duration at first — for those, this tool quietly falls back to a full local decode to get an exact number.
What counts as "fits free transcription"?
Clabrate's free browser transcriber handles clips up to 10 minutes each. Anything at or under that shows a green fit indicator with a link to transcribe it; anything longer is flagged with a link to the audio splitter so you can cut it into pieces first.
How accurate is the speaking-time estimate?
It's a planning estimate, not a stopwatch. It uses your chosen words-per-minute pace plus optional padding for natural pauses (about 0.4s per sentence end, 1.0s per paragraph break). Real delivery varies with pacing, emphasis, and pauses for slides or breath, so treat it as a solid ballpark for scripting a voiceover or podcast segment.
Can I paste a subtitle file (SRT/VTT) instead of a script?
Yes. Drop a .srt or .vtt file into the script panel and the tool strips cue numbers, timestamp lines, and WEBVTT/NOTE headers automatically, leaving just the spoken text for word and time counting.
Is there a limit on how many audio files I can check at once?
No hard cap — this runs entirely in your browser tab, so the practical limit is your device's memory. Reading durations is cheap enough that dropping dozens of files at once is fine.