The simplest way depends on what you already have

Attaching videos together means combining separate video files into one continuous file — sometimes called concatenating or merging. The easiest method depends on three things: what operating system you use, whether your videos are already in the same format, and how much control you want over transitions or timing.

On Windows, the built-in Photos app can combine videos without installing anything. On Mac, iMovie does the same. If you want more control — adding transitions, adjusting audio levels, or cutting out sections before joining — you need video editing software like DaVinci Resolve (free on Windows and Mac) or CapCut (free on Windows, Mac, and mobile). If your videos are in different formats or frame rates, editing software handles the conversion automatically; simpler tools sometimes refuse to work until you convert them first.

Key Takeaways

  • Windows Photos and Mac iMovie can join videos in seconds without learning editing software, but offer no control over how they connect.
  • DaVinci Resolve and CapCut are free editing programs that let you add transitions, trim clips, and adjust audio before joining them.
  • Videos must be in the same format to join them in Photos or iMovie; editing software converts formats automatically.
  • The final file size depends on the original videos' resolution and length, not the joining method — a 1-hour video stays roughly the same size whether you join it as one file or three.

Using Windows Photos to join videos

Open the Photos app (built into Windows 10 and later). Click the folder icon in the top left, navigate to the folder holding your videos, and select all the videos you want to join in the order you want them. Right-click and choose "Open with" > "Photos".

Once the videos are open in Photos, click the three-dot menu in the top right and select "Create" > "Video with music". Photos will show you a timeline with your videos in order. Click "Save a copy" at the bottom right. Photos exports the joined video to your Videos folder as an MP4 file. The process takes a few minutes depending on video length and your computer's speed.

This method works only if all your videos are already in MP4 format and shot at the same resolution. If they are in different formats (MOV, AVI, WebM), Photos will either refuse to open them or produce a corrupted output file. If you need to join videos in different formats, skip to the DaVinci Resolve section below.

Using Mac iMovie to join videos

Open iMovie from your Applications folder. Click "Create New" and select "Movie". Drag your video files into the timeline at the bottom of the window in the order you want them. iMovie automatically places them end-to-end with no gap.

If you want to add a transition between videos (a fade, dissolve, or other effect), double-click the space between two clips and choose a transition type. When you are ready to save, click "File" > "Share" > "File". Choose your resolution (1080p is standard for most uses), and iMovie exports the joined video as an MP4 file to wherever you choose on your Mac.

Like Photos on Windows, iMovie works best when all videos are already in the same format. It handles MOV files natively since that is Apple's format, but MP4 files sometimes cause iMovie to slow down or crash during export. If you run into problems, DaVinci Resolve is more reliable for mixed formats.

Using DaVinci Resolve for more control

DaVinci Resolve is free editing software that handles any video format and gives you precise control over how clips connect. read it from Blackmagic Design's website (the free version is called DaVinci Resolve, not Studio). Install it and open the program.

Click "New Project" and set the resolution to match your videos (1080p is standard; check one of your video files by right-clicking it and selecting Properties on Windows or Get Info on Mac). Click "Create". Drag your video files into the timeline at the bottom in the order you want them. DaVinci Resolve automatically places them end-to-end with no gap between them.

To add a transition, click the small icon between two clips on the timeline that looks like two overlapping squares. Choose a transition type from the menu — Dissolve is the most common. Adjust the length by dragging the transition bar left or right. When finished, click "File" > "Export" > "Add to Render Queue". Choose MP4 as the format, set the resolution to match your original videos, and click "Start Render". DaVinci Resolve exports the file to your chosen folder.

DaVinci Resolve is slower than Photos or iMovie because it is doing more work, but it handles format mismatches automatically and rarely crashes. If you have videos shot on different phones or cameras, this is the safest choice.

Using CapCut on phone or computer

CapCut is free editing software available on iPhone, Android, Windows, and Mac. On a phone, open CapCut and tap "New project". Select all the videos you want to join from your camera roll. CapCut places them in the timeline in the order you selected them.

Tap between two clips to add a transition, or leave them joined with no transition. When finished, tap "Export" in the top right. Choose your resolution (1080p is standard) and tap "Export". CapCut saves the joined video to your camera roll.

On Windows or Mac, the process is similar: open CapCut, create a new project, drag videos into the timeline, add transitions if you want them, and click "Export". CapCut is faster than DaVinci Resolve on most computers and handles format mismatches well. The trade-off is that it offers fewer advanced controls — you cannot adjust audio levels separately or add effects to individual clips as easily.

Preparing videos before joining them

Before you join videos, check that they are all the same resolution. If one video is 1080p and another is 4K, the editing software will either shrink the 4K video to fit or stretch the 1080p video, both of which look bad. Right-click each video file and select Properties (Windows) or Get Info (Mac) to see the resolution listed.

If your videos are different resolutions, convert them all to the same size before joining. DaVinci Resolve can do this during export, but it is faster to convert them first using free software like HandBrake. Open HandBrake, drag in a video, set the resolution to 1920x1080 (standard 1080p), and click "Start Encode". Repeat for each video that needs conversion.

Also check the frame rate — the number of frames per second (fps). Most phone videos are 30 fps; some are 60 fps. Mixing them usually works fine, but if you notice stuttering or jerky playback after joining, convert all videos to 30 fps using HandBrake before trying again.

Choosing a file format for the final video

All the methods above export to MP4, which is the most compatible format — it plays on any phone, computer, or streaming platform without conversion. If you need a different format, DaVinci Resolve offers the most options: click "File" > "Export" and choose from MP4, MOV, WebM, or others depending on where you plan to use the video.

The file size of your joined video depends on the original videos' resolution and length, not on the joining method. A one-hour video shot at 1080p is roughly 1.5 to 2 gigabytes whether you join it as one file or three separate files. If file size matters — for example, if you are uploading to a platform with a size limit — trim unnecessary sections before joining using any of the editing software above.

Frequently Asked Questions

Can I join videos that are different resolutions?

Yes, but the result will look stretched or shrunk. All editing software will force them to match, usually by shrinking the larger one. To avoid this, convert all videos to the same resolution first using HandBrake or another converter, then join them.

What if the videos are in different formats like MP4 and MOV?

Photos and iMovie may refuse to work or produce corrupted files. DaVinci Resolve and CapCut handle mixed formats automatically. If you want to use Photos or iMovie, convert all videos to MP4 first using HandBrake.

How long does it take to join videos?

Photos and iMovie take a few minutes depending on total video length and your computer speed. DaVinci Resolve takes longer because it re-encodes the entire video. CapCut is usually faster than DaVinci Resolve. A one-hour video typically takes 10 to 30 minutes to export.

Can I trim or cut videos before joining them?

Photos and iMovie do not offer trimming. DaVinci Resolve and CapCut let you cut sections out of each clip before joining. Drag the edge of a clip on the timeline to trim it, or right-click and select "Trim" to remove unwanted sections.

What happens to audio when I join videos?

All methods preserve the original audio from each video and play it in sequence. If you want to adjust volume, add background music, or fade audio between clips, use DaVinci Resolve or CapCut, which offer audio controls that Photos and iMovie do not.