Free Online Video Merger

Merge & Combine Multiple Video Files

Join multiple video clips into one seamless video. Combine MP4, MKV, AVI, MOV, and WebM files in any order — perfect for stitching together segments, parts, or clips from the same or different sources.

Join up to 10 video files at once Supports mixed input formats No watermarks or time limits

Drop multiple files here

or browse files

Add at least 2 files • They will be combined in order

SSL Encrypted

Files deleted in 2h

Fast processing

No signup needed

Simple & Fast

How to Use Video Merger

Convert your files in three simple steps — no software, no signup.

Upload Multiple Videos

Upload two or more video clips you want to join. Mix formats — MP4, MKV, AVI, MOV, WebM, and WMV are all accepted together.

Arrange the Order

Drag the clips into the playback order you want. The merger concatenates videos in the sequence you set.

Download Merged Video

Download your combined video as a single MP4 or MKV file. Transitions are seamless — no visible cut or gap between segments.

Features

Why Use Video Merger?

Multi-Clip Assembly

Combine drone footage, GoPro clips, and phone recordings into a single continuous video without a video editor.

Video Part Joining

Re-join a multi-part video download (Part 1, Part 2, etc.) into a single continuous file for easier playback and storage.

Presentation Compilation

Combine multiple screen recordings, lecture captures, or webinar segments into one complete presentation video.

Mixed Format Input

Upload files from different cameras and devices in different formats — the tool normalises them all before merging so formats are handled automatically.

Flexible Output Format

Choose MP4 for maximum compatibility or MKV for lossless quality preservation. The output format selector appears after uploading.

Secure Processing

All uploaded videos are processed in an isolated server environment and deleted automatically within one hour.

Compatibility

Supported Formats

All the formats you need, all in one place.

Format	Description	Extension	Best Used For
MP4 + MP4 → MP4	Seamless MP4 video concatenation	`.mp4`	Social media video series, vlogs, tutorials
MKV + MKV → MKV	Lossless MKV chapter joining	`.mkv`	Multi-episode shows, long-form content
MOV + MOV → MP4	Combine Apple QuickTime clips	`.mov`	iPhone video compilation, Final Cut export
MIXED → MP4	Combine different formats to MP4	`mixed`	Multi-device footage into one deliverable
AVI + MP4 → MP4	Legacy and modern video combined	`mixed`	Archive footage with new recordings
WEBM + MP4 → MP4	Web and local video combined	`mixed`	Web video downloads with local captures

FAQ

Frequently Asked Questions

You can merge up to 10 video files in a single operation. Each file can be up to 200 MB, with a total input limit of 500 MB. For larger projects, merge in batches and then merge the results.

For the cleanest result, input videos should ideally have the same resolution and frame rate. If they differ, the tool will scale all clips to match the first video's settings before concatenating.

No — the merger produces seamless joins between clips. There are no visual gaps, black frames, or audio glitches at transition points.

This tool performs simple concatenation (direct joins). For crossfades or other transition effects between clips, a video editing application like DaVinci Resolve or Adobe Premiere is recommended.

Yes, as long as each video file has its own audio track. All audio tracks are processed alongside the video. For mixing separate video and audio files, a video editing tool is more appropriate.

You can select the output format after uploading. MP4 is recommended for sharing and compatibility. MKV is recommended for preserving quality and lossless source material.

Real-World Uses

Who Uses Video Merger?

From everyday users to professionals — see how people rely on this tool every day.

Travel Vloggers

Multi-Clip Travel Videos

Stitch together clips from phones, GoPros, and drones into one continuous travel video without a video editor.

Film Downloaders

Re-join Split Downloads

Rejoin multi-part video files (Part 1, Part 2, Part 3) from split archives or download managers into a single seamless file.

Course Creators

Lecture Compilation

Combine multiple screen recording segments of a lecture series into one complete video for distribution to students.

Sports Fans

Highlights Reel Assembly

Use the Video Cutter to extract individual highlights, then merge them into one shareable highlights reel. No editing software needed.

Corporate Teams

Webinar Segment Joining

Combine multiple recorded webinar segments (after breaks or reconnections) into one clean, continuous recording for distribution.

Indie Filmmakers

Scene Concatenation

Quickly join rough scene exports for dailies review or rough cut assembly without a full NLE timeline setup.

Why TransmuteBox?

TransmuteBox vs. Alternatives

See how we compare to desktop software and other online converters.

Feature	FFmpeg CLI	Other Online
Up to 10 clips per merge	Unlimited	2–5 clips
Mixed format input
Resolution normalisation
Seamless joins (no gaps)		Varies
MP4 & MKV output		MP4 only
No install required
Files auto-deleted after 2 h		Varies

Under the Hood

Technical Specifications

Built on industry-standard open-source tools for maximum quality and reliability.

Limits & Restrictions

Max clips: 10 per merge
Max total input: 500 MB
Output: MP4 or MKV

FFmpeg Video Merge Concatenate Join Videos MP4 MKV

Conversion Engine

FFmpeg 6.x · concat demuxer · filter_complex for mixed-format input

Output Quality

Stream concat for same-format clips · re-encode CRF 23 for mixed formats

Average Speed

Near-instant for same-codec clips · 60–120 s per 10-min mixed-format merge

Data Security

HTTPS transfer · isolated temp dir · auto-purged in 2 h

Max clips

10 per operation

Mixed formats

Auto-normalised before merge

Resolution

Matched to first clip

Complete Guide

Video Merging Explained: Concatenation, Format Mixing & Seamless Joins

Merging video files involves more technical complexity than simply gluing clips together. When formats, resolutions, or frame rates differ, the merger must normalise the clips before joining them. Here's how video merging works and how to get the best results.

How Video Concatenation Works

The simplest case of video merging is concatenation — joining clips in sequence where all clips have identical codecs, resolutions, frame rates, and audio format. In this case, FFmpeg's concat demuxer can combine them nearly instantly without any re-encoding.

When clips differ in format, resolution, or codec, they must first be decoded and normalised to a common specification before concatenation. This re-encoding step takes time proportional to the total clip length but ensures a seamless, glitch-free output.

Handling Mixed Format Input

A common scenario is merging clips from different devices — an iPhone MOV, a GoPro MP4, and a drone MKV. Each has different resolutions (vertical 1080×1920, horizontal 3840×2160, horizontal 2704×1520), different frame rates (30fps, 60fps, 24fps), and different codecs.

TransmuteBox normalises all clips to a common resolution, frame rate, and codec before merging. The first clip's settings are typically used as the target specification, with all other clips scaled and re-sampled to match.

Resolution Matching: Why the First Clip Matters

When merging clips of different resolutions, all clips are scaled to match the first clip's resolution. This means:

If your first clip is 1920×1080 and the second is 3840×2160, the 4K clip is downscaled to 1080p.
If your first clip is 1280×720 and others are 1080p, all are downscaled to 720p.

To preserve the highest quality, upload your highest-resolution clip first, or convert all clips to the same resolution before merging using our Video Converter.

The Cut-Then-Merge Workflow

For creating highlight reels, compilation videos, or summary edits without a full video editor, the cut-then-merge workflow is highly efficient:

Use the Video Cutter to extract each desired segment from your source videos.
Upload all extracted clips to the Video Merger in the desired order.
Download the merged result as a single MP4 or MKV.

This approach works well for sports highlights, "best of" compilations, and lecture summary videos.

Output Format: MP4 vs MKV for Merged Videos

When choosing the output format for merged video:

MP4: Best if you plan to share the video on social media, via email, or with people on Windows/Android devices. Maximum compatibility.
MKV: Best if the merged video is going into a media server library (Plex, Kodi, Jellyfin), or if you're preserving quality for further editing. More flexible container with no compatibility trade-offs in dedicated players.

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