Does a longer result add new music or repeat a section?
No. A lower tempo stretches the existing content. It does not generate an ending, loop a section or add bars to an arrangement.
A DIFFERENT LENGTH, THE WHOLE RECORDING
Fit Audio to a Target Duration
Without Cutting It
Have a 33-second recording and a 30-second space? Work out a tempo percentage that brings the whole file closer to the length you need while keeping its pitch.
Enter a calculated tempo from 50–150% for a source file up to 5 minutes and 100 MB. There is no target-duration field; check the final download in your destination editor.
Adjust your audio’s duration for free
The audio tool opens on the Pitch Tempo home page.
How do you make audio fit a specific length?
Convert both lengths to seconds, then calculate tempo percentage = original duration ÷ target duration × 100. Enter that percentage in Pitch Tempo and leave pitch at 0 semitones. A value above 100% shortens the file; a value below 100% makes it longer without deliberately transposing its pitch.
This is useful when you want to keep the whole recording and only need a modest timing adjustment. It is a manual calculation: the site accepts a tempo percentage, not an end time. Check the downloaded result in the editor or player where you intend to use it.
Calculate the percentage from seconds, not BPM
You do not need to detect a beat to change duration. Speech, a music bed or an unmetered passage can all be adjusted using their total file length. Include the beginning, ending and any silence in that measurement.
| Source length | Target length | Calculation | Tempo setting |
|---|---|---|---|
| 33 seconds | 30 seconds | 33 ÷ 30 × 100 | 110% |
| 48 seconds | 60 seconds | 48 ÷ 60 × 100 | 80% |
| 2:10 (130 seconds) | 2:00 (120 seconds) | 130 ÷ 120 × 100 | 108.33% |
Convert minutes properly: 2:10 means 130 seconds, not 2.10 minutes. The percentage describes speed, not the proportion of duration to retain. At 110% tempo, a file lasts about 90.91% as long; it does not become 110% as long.
To check a setting in the other direction, use expected duration = original duration ÷ (tempo percentage ÷ 100). At the rounded 108.33% setting, a 130-second source has a calculated duration of about 120.004 seconds before allowing for processing and file-format differences.
Check whether your target is within reach
The available tempo range is 50–150%. For any source, the shortest nominal result is two-thirds of its original duration, and the longest is twice its duration. A two-minute recording can therefore become approximately 80 seconds to four minutes long.
A 30-second file cannot become ten seconds here: that would require 300%. Stretching it to 90 seconds would require about 33.33%, also outside the range. A larger mismatch may need an edited script, a shorter musical arrangement or a separate audio editor.
The upload limit is five minutes and 100 MB. That limit applies to the original file; an allowed five-minute source slowed to 50% can produce an approximately ten-minute export. Review the current service limits before preparing a long source.
Fit a voiceover or music bed to a clip
For narration that slightly overruns a visual sequence, a small increase may bring the final word closer to the intended endpoint. Listen for rushed syllables, unnatural breaths and pauses that become too short. Preserving pitch does not guarantee that a strongly accelerated voice will still sound conversational.
For a music bed, every event moves proportionally: the opening beat, transitions and final chord all arrive at different times. Matching the total length does not separately align a chorus with a scene change. Existing lip-sync and other internal cues may also move out of alignment.
Use your video or audio editor to place the downloaded file and check those cues. Pitch Tempo processes audio files only; it does not import video, edit a timeline or synchronize speech to faces.
Adjust the whole file and verify the finish
Measure the actual source
Read its full duration in a reliable player or editor. If unwanted silence makes the measurement misleading, trim it in another editor first; a tempo change will shorten or lengthen that silence too.
Enter your calculated value
Upload the file on the Pitch Tempo home page and choose Change pitch / tempo. Keep pitch at 0 and type the percentage into the tempo number field, rounding to its supported 0.01% increments.
Check the sound with a preview
Select Listen preview. It uses the first 20 seconds of source audio, so it helps you judge the pace and sound but cannot verify the complete file’s endpoint. Changing a setting requires a new preview.
Export and measure the complete result
Choose the download action and the format accepted by your destination. WAV is a practical choice for further editing. Check the downloaded audio’s actual duration and placement in that editor.
Rounded percentages, processing boundaries and encoded-file padding mean that a calculated target is not a guarantee of sample- or frame-exact length. If an exact endpoint is mandatory, make the final adjustment in a timeline editor. Export completes editing in this chat; another full attempt requires a new upload.
Questions about changing audio duration
Can I change only one pause or sentence?
No. The percentage applies uniformly to the entire file. Local timing edits require a tool that lets you select and move individual regions.
Do I need to find the song’s BPM first?
No. This calculation uses source and target durations. BPM is useful for a musical tempo target, but it is not needed to fit the complete file into a chosen length of time.
Give your recording a useful new length
Measure the source, calculate the percentage and try a modest adjustment. Export the complete audio when it sounds right, then check its timing where you plan to use it.