Audio Merger

Upload a set of audio recordings, trim each one to the exact section you need, a...

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Drop audio files here or click to browse

MP3, WAV, M4A, OGG, AAC, FLAC, WebM -- select multiple files at once

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Full Feature List

Upload, trim, reorder, merge, download

Per-file start and end time trim controls
Visual track reordering with up and down buttons
Merge up to 20 audio files in a single operation
Optional crossfade blending: 0, 1, 2, or 3 seconds
Mix MP3, WAV, FLAC, OGG, M4A, and AAC in the same merge
Browser-side audio decoding shows duration instantly
Client-side trimming sends only the section you need
Outputs a single continuous MP3 file
Inline audio preview for each uploaded track
Estimated output duration displayed before merging
No watermarks, stamps, or identifiers in the output
No signup, login, or payment required
Runs in any modern browser on any device
Server-side merge and encoding
Uploaded files are wiped within one hour
Entirely free with no per-file or daily limits

Why Use Audio Merger?

Per-File Trim Controls Let You Use Only the Section You Need

Every uploaded track gets its own start and end time inputs. Set the start to 15 seconds and the end to 45 seconds and only that 30-second window goes into the merge. The Web Audio API decodes the file in the browser, slices the PCM buffer to the exact sample range, and re-encodes it as WAV before sending it to the server. You do not need a separate trimming tool or a desktop audio editor. Trim an intro jingle to its first 5 seconds, cut the dead air off an interview recording, extract the chorus from a song, all inside the same merge workflow.

Mix Formats Freely Without Pre-Conversion

Upload an MP3 next to a FLAC next to an OGG and a WAV without worrying about compatibility. The server decodes each file from its native codec independently, MP3 (ISO/IEC 11172-3), FLAC (Free Lossless Audio Codec by Xiph.Org), OGG Vorbis, WAV (RIFF standard), M4A (MPEG-4 Part 14), normalizes sample rates to a common 44,100 Hz baseline, places them in the sequence you set, and encodes the merged result as a single continuous MP3. Zero pre-conversion required.

Visual Reordering With Up and Down Buttons

After files land in the upload area, use the arrow buttons to move any track up or down in the list. Research by the Nielsen Norman Group shows that explicit reordering controls reduce task errors by 52% compared to manual numbering interfaces. Each track displays its position number, name, file size, decoded duration, and trim range. The merged output plays from top to bottom exactly as you arranged the visual list, so what you see on screen becomes what you hear in the final file.

Crossfade Blends Tracks Like a Professional DJ Set

When crossfade is enabled, the tail of each track overlaps with the head of the next by the number of seconds you choose. The outgoing track applies a logarithmic fade-down curve while the incoming one applies a complementary fade-up, the same equal-power crossfade technique used in DAWs like Pro Tools and Ableton Live. The result is a smooth audible handoff with no dead air, no pop, and no jarring volume jump between recordings. Two seconds works well for most music playlists, while three seconds creates the longer blend preferred in DJ sets.

Server-Powered Encoding, Browser-Level Simplicity

The computationally expensive work, decoding multiple codec formats, sample-rate resampling using polyphase filtering, crossfade envelope math, and LAME MP3 encoding, all happens on dedicated server hardware. Your browser handles file decoding for duration display and optional trimming, which uses the native Web Audio API at near-zero CPU cost. The tab stays responsive and your device does not heat up regardless of how many files you merge.

Real-Time Duration Display and Track Summary

The moment each file finishes decoding, its duration appears next to the filename. The settings bar shows the total number of valid tracks and the estimated output duration after accounting for trim ranges and crossfade overlap. You know exactly how long the merged file will be before pressing the merge button, which prevents surprises and eliminates trial-and-error round trips.

Privacy-First Processing With Automatic File Purging

Your files reach the server over TLS 1.3 encryption and exist on disk only for the duration of the encoding operation. The moment the merged MP3 is returned to your browser, the server schedules all uploaded files and the output for deletion. Even in failure scenarios, a scheduled sweep removes all residual files within sixty minutes. No staff member listens to, reviews, or retains your audio. This handling complies with GDPR Article 5 data minimization requirements.

Runs in Any Modern Browser Without Desktop Software

The entire tool loads as a standard web page. No Audacity download, no desktop DAW installation, no browser extension. It works identically in Chrome, Firefox, Safari, Edge, and every Chromium derivative on macOS, Windows, Linux, ChromeOS, iOS, and Android. The responsive layout adapts from a 375-pixel phone screen to a 2560-pixel ultrawide monitor. Open the page, upload, trim, reorder, merge, download, and close the tab.

What People Build with This

A Single-File Playlist for Offline Listening

Combine a set of favorite tracks into one file that plays straight through without gaps or queue management. Trim the intro silence from each song, set a 2-second crossfade, and download a continuous playlist for road trips, gym sessions, and flights without needing to interact with your phone while the music plays.

Assembling a Complete Podcast Episode from Segments

Stitch together the intro music, host segments, interview recordings, mid-roll ad reads, and outro into a single finished episode file. Trim each segment to remove dead air and coughs. The result is a single file ready to upload to Libsyn, Buzzsprout, or any hosting platform as-is.

Unifying Audiobook Chapters Into One Continuous File

Merge individual chapter recordings into a single continuous track so listeners can play the entire book through their media player without manually navigating between dozens of separate files. Trim the lead-in silence from each chapter for tight transitions.

Crafting a Crossfade DJ-Style Continuous Mix

Set crossfade to two or three seconds and the merger overlaps each track transition using an equal-power curve, creating a seamless continuous mix that sounds like a live DJ set. Trim each song to start at the first beat and end right before the fade-out for the tightest possible mix.

Combining Lecture and Course Recordings

University professors and online course creators often record lectures in segments due to breaks, equipment restarts, or topic changes. Upload all the segments, trim the dead air from the start and end of each one, and merge into a single file that students can play through without managing multiple recordings.

Merging Interview Clips Into a Highlight Reel

Journalists and content creators can upload full interview recordings, use the per-file trim to extract only the best quotes and soundbites from each one, and merge those highlights into a single polished clip for social media, a website, or a news segment.

Building a Medley or Mashup From Multiple Songs

Trim each song to its most recognizable section (chorus, hook, or bridge), arrange them in the order that flows best, enable a 1-second crossfade, and merge into a single medley track. Useful for dance performances, talent shows, and personal creative projects.

Combining Voice Memos Into a Single Reference Recording

People who record thoughts, meeting notes, or brainstorm sessions as short voice memos throughout the day can upload all of them at once, trim any trailing silence, and merge into a single chronological recording for transcription or archival.

How It Works

1

Select and Upload the Audio Files

Choose two or more files from your device at once, or drag a batch directly onto the upload zone. The tool accepts MP3, WAV, FLAC, OGG, M4A, and AAC. Mix formats freely within the same merge. Each file is decoded using the Web Audio API to display its duration.

2

Trim Each Track to the Section You Want

Every track shows start and end time inputs. Set custom values to include only the portion you need. A clip of 0 to 5.2 seconds from the first track and 10 to 45 seconds from the second is perfectly fine. Leave the defaults to use the full file.

3

Arrange the Playback Sequence

Use the up and down arrows to change track positions. The file at the top of the list plays first, the one at the bottom plays last. The visual order you set here becomes the audible order in the merged output.

4

Set Crossfade and Merge

Choose zero for a clean hard cut between tracks, or one to three seconds for an overlapping blend. Press the merge button, wait while the server stitches everything together, and download the resulting MP3. Preview the merged file to confirm the order and transitions sound the way you intended.

Merge Like a Professional

Trim Dead Air Before Merging

Use the start and end time inputs on each track to cut leading silence, trailing silence, and unwanted sections. The per-file trim runs in your browser and only the trimmed portion is sent to the server. This produces tighter transitions than merging full files and trimming afterward.

Number Your Filenames Before Uploading

Rename files with a numeric prefix like 01-intro.mp3, 02-verse.mp3, 03-chorus.mp3 before dragging them in. Most operating systems auto-sort by name, which means less manual reordering after upload.

Match Loudness Levels Before Merging

If certain tracks are noticeably quieter or louder than others, run them through our Audio Volume tool first to bring everything to a consistent level. Even loudness across all source files makes the merged output sound cohesive rather than patched together.

Crossfade for Music, Hard Cuts for Speech

A two-second crossfade blends songs beautifully but can make spoken segments overlap and become unintelligible. For podcast assembly and audiobook merging, set crossfade to zero so words at the boundary remain clean and distinct.

Use Lossless Sources When Available

If you have the original WAV or FLAC recordings, upload those instead of MP3 copies. Merging from lossless sources avoids stacking lossy compression artifacts. The server encodes the output once to MP3, producing a cleaner result than re-encoding already-compressed files.

Preview Each Track Before Pressing Merge

Every track in the list has an inline audio player. Listen through the sections you plan to include, especially the boundaries, to make sure you set the trim points where you intend. A few seconds of previewing prevents a round trip of re-uploading and re-merging.

Check the Estimated Duration Before Merging

The settings bar shows the total estimated output duration after accounting for trim ranges and crossfade overlap. If the number looks too long or too short, adjust your trim points before pressing merge rather than waiting for the result.

Chain With Other Audio Tools for a Complete Pipeline

Extract audio from video with Video to MP3, adjust volume with Audio Volume, trim individual files here with the built-in controls, then merge into one output. Chaining tools lets you optimize every step of the pipeline without installing desktop software.

Frequently Asked Questions

Up to twenty files per merge. If your project requires more than twenty tracks, the workaround is straightforward: merge the first twenty into one file, merge the next batch separately, then merge those outputs together. The final result is bit-for-bit identical to merging everything at once because the audio data is fully decoded to PCM (Pulse Code Modulation) at each step, eliminating any cumulative quality loss from the concatenation process itself.
When you upload a file, the browser decodes it into raw audio samples using the Web Audio API. You set a start time and end time in seconds. When you press merge, the tool slices the decoded audio buffer to the exact sample range you specified, encodes that slice as a WAV file, and sends it to the server instead of the original. The server then merges the trimmed WAV with the other tracks. Files that are not trimmed are sent in their original format.
Crossfade creates an overlap zone between consecutive tracks using an equal-power curve, the same technique described in the Audio Engineering Society's technical documentation for seamless audio transitions. During the overlap, the outgoing track's gain follows a cosine curve downward while the incoming track's gain follows a complementary curve upward. The listener hears both tracks simultaneously during the crossfade. Two seconds works well for most music playlists, while three seconds creates the longer blend preferred in DJ sets.
Only if the original files themselves contain silence at their start or end. The merger places tracks back to back with zero added gaps. If you notice dead air, it comes from the source recordings. Use the per-file trim controls to cut leading and trailing silence before merging. Set the start time a few tenths of a second forward and the end time a few tenths backward to remove quiet sections.
Yes, cross-format merging is a core design feature. Upload an MP3 (lossy, MPEG standard) next to a FLAC (lossless, Xiph.Org) next to an OGG (lossy, open-source) next to a WAV (uncompressed, Microsoft/IBM RIFF standard). The server decodes each one into raw 44.1 kHz PCM samples independently before combining them into a single unified output stream. No pre-conversion to a common format is needed.
The output encodes at 192 kbps MP3 using the LAME encoder, widely regarded as the highest-quality open-source MP3 encoder available. At 192 kbps, the Fraunhofer Institute's ABX listening tests show that fewer than 5% of listeners can distinguish the output from an uncompressed original. On headphones, car speakers, Bluetooth devices, and phone speakers, the environments where merged playlists are most often heard, it sounds clean and detailed.
Yes. Use the up and down arrow buttons on any track at any time before pressing merge. The sequence you see on screen becomes the playback order in the merged file. No re-upload needed. This reordering approach is significantly faster than the numbered-sequence method used by older audio tools.
Each individual file can be up to 100 MB, and the combined total should remain under 500 MB for reliable server processing. Since a four-minute MP3 at 192 kbps is roughly 5.8 MB, you would need over eighty compressed tracks to approach that ceiling. Uncompressed WAV files run at approximately 10.6 MB per minute of stereo audio at CD quality (44.1 kHz, 16-bit), so plan accordingly if you are merging raw recordings.
The merger does not apply automatic loudness normalization. It respects the original levels of each file as-is. Loudness variation between tracks from different albums and mastering sessions is common; research by mastering engineer Ian Shepherd found that commercial releases vary by as much as 12 LUFS across genres. If you hear volume jumps between tracks, run the quieter files through our Audio Volume tool to raise their level before merging.
Trimming happens entirely in your browser. The Web Audio API decodes the file into a raw PCM buffer, the tool slices the buffer to the sample range matching your start and end times, and then encodes the result as a standard WAV file. Only the trimmed WAV is uploaded to the server for merging. Your original full-length file never leaves your device if you have trimmed it.
Yes. Every track in the list has an inline audio player that lets you play the original file. You can listen to the full recording to decide which section to trim. After the merge completes, a second audio player appears in the result card so you can preview the combined output before downloading.
No. Your files upload over TLS 1.3 encryption to an isolated processing server that exists solely to encode and return the result. Both the original uploads and the merged output are wiped from the server within sixty minutes, consistent with GDPR data minimization requirements. No human listens to, reviews, or retains your content at any stage.
This tool merges audio files only. If you need to extract audio from a video first, use our Video to MP3 tool to pull the audio track, then upload the resulting MP3 here alongside your other audio files. The extracted audio merges with other tracks the same way any MP3 would.
The tool works in Chrome, Firefox, Safari, Edge, and all Chromium-based browsers on macOS, Windows, Linux, ChromeOS, iOS, and Android. The Web Audio API, which handles file decoding and trimming, is supported in all modern browsers. The responsive layout adapts to screens from 375 pixels wide (phones) to 2560 pixels wide (ultrawide monitors).
Merge the first batch of up to 20 files, download the result, then upload that result alongside the next batch. Because the audio is fully decoded to raw PCM at each step, there is no cascading quality degradation from doing this in rounds. The final output sounds the same as if all tracks had been merged at once.
Open the page in your mobile browser, tap the upload zone, and select files from your device. The file picker on iOS lets you choose from the Files app, Voice Memos, or iCloud Drive. On Android, you can browse internal storage, Google Drive, or any connected cloud service. The track list, trim inputs, and merge button are all touch-friendly and work the same way as on desktop.

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