Video files are huge by nature. Without compression, we couldn't send video by email, watch Netflix on mediocre Wi-Fi, or hide our retirement savings in old VCRs.

Fortunately these days, we can record and resize video without losing quality. Video compression shrinks file sizes, making them easy to distribute on any platform and with almost any internet bandwidth. However, it requires familiarizing with file formats, resizing, and video bitrates. 

To help make sure your content is accessible to viewers, here’s a complete step-by-step guide on how to compress video using a variety of video editing techniques.

What is video compression?

Video compression is the process of reducing video file size while still retaining the necessary video data. You do this using codec software, which decides what information is required for the video to maintain its quality and what information can be discarded. There are a few different video codecs—all responsible for compressing (and decompressing) the video in unique ways.

What makes video files so big?

There are three core elements that determine the size of a video file: the video resolution, the bitrate, and the encoding method. 

Understanding how they work lets you compress video files without compromising the visual appeal. That way, you can avoid quality loss and save storage space. 

Resolution

Resolution is the actual size, in pixels, of your video image. When people refer to a video in terms of “1080p” or “4K,” they’re referencing the video’s resolution. A 1080p high-definition video, for example, is 1,920 pixels wide and 1,080 pixels tall. 

That video has over 2 million pixels per frame. Each pixel contains unique data about its color and brightness. Multiply that by the number of frames per second—commonly between 24 and 60 frames per second—and you can see why uncompressed video files are so large.

Bitrate

Bitrate is the amount of data being transferred at a given time. It’s typically measured in bits per second (bps), kilobits per second (Kbps), or megabits per second (Mbps). 

In general, higher bitrates can transfer more data per second, resulting in higher video quality, but also larger video files. At the other end of the spectrum, lower bitrates can transfer less data, resulting in smaller files.

You can encode a video using constant bitrate (CBR) or variable bitrate (VBR). CBR maintains a consistent rate for the duration of the video, whereas VBR will adjust the rate depending on the complexity of the video from moment to moment. 

Encoding

Encoding is the process of compressing video files into a specific file type like AVI, MOV, WMV, or MPEG. Some video formats and codecs compress data more efficiently. Selecting an efficient video codec in your video editor, like H.264, often leads to high-quality videos with reduced file sizes. 

There are two key elements of a video file during the encoding process:

1. Container. People often refer to the container as the "file format." Common examples of a container would be MP4 and MOV file types.
2. Video codec. The codec is held within the container and is responsible for applying the compression. Different codecs, including lossless codecs and lossy codecs, handle compression in different ways. Think of it as using different mathematical methods to solve the same problem.

5 ways to compress video files

Now that you know what makes a video file so big, we’ll share five different tutorials you can use to compress videos. 

1. How to compress a video by converting the video format

Converting your video to another format may shave down its size. For example, a popular video format for online use is MP4 (or MPEG-4) using the H.265 (HEVC) codec. 

This particular format is well-regarded because of its high compression, good video quality, and high compatibility. To convert a video to another format in a video editing program, follow these steps:

1. Locate your video file: Find the video you want to compress on your device.
2. Open a video editing program: Load your video file into video editing software. Popular choices include Handbrake, iMovie, and Descript.
3. Choose a new format and codec: Opt for a more compressed format like MP4 with the H.265 (HEVC) codec, which is known for its high compression and good video quality.
4. Export your video: During the export process, select your desired format and codec. 
5. Save your video: Save the newly compressed video to your device and verify the reduction in file size.

Keep in mind that not every video may be suited to each format. Different codecs handle the compression process differently—you may find one format and codec struggles with your particular video while another retains more detail. 

2. How to compress a video by trimming It

Is there extra time at the beginning or end of the video? Maybe there are sections in the middle that are unnecessary? Shortening the overall runtime of the video by trimming out these unneeded parts will help reduce your video file size. 

You can do this with any video editing software. The workflow will be similar for most applications including iMovie, Adobe Premiere, or Descript’s video editor.

Here’s how to reduce the length of your video using most video editing software:

1. Import the video file to a video editing tool like Descript.
2. Add the video to the timeline.
3. Use the slice, cut, or trim tool to shorten the beginning and end or remove any parts of the video file you don’t need. In Descript, you can also delete unnecessary words from the transcript and those edits will appear in your footage.
4. Select Export, share, or render depending on the software you are using. (This would be a good time to incorporate the next few suggestions as you set the encoder options to further reduce file size.)

3. How to compress a video by reducing the resolution

When choosing a technique to compress your video, think about where your video will be viewed. If you intend to upload the video to YouTube and the original file’s resolution is larger than 1080p, you could reduce file size greatly by lowering the resolution to 1920 pixels by 1080 pixels.

But if you’re uploading a video to social media or a platform where it’ll mostly be seen on mobile devices, you can lower the resolution even further. While most mobile devices are able to display very high-resolution images and video, the screens are still pretty small—so the reduced quality of a low-resolution video won’t be as noticeable. 

For social media, a resolution of 720p, which is 1280 pixels by 720 pixels, may be a good choice. Square videos work just as well, depending on the platform. You can easily reduce the file size by cropping a 1920 x 1080 video file to a square 1080 pixels by 1080 pixels.

Here’s how to reduce the resolution of a video by cropping it:

1. Determine the viewing platform: Understand where your video will be seen—on YouTube, social media, or mobile devices—to choose the appropriate resolution.
2. Open your video editing software: Import your video file into a video editing program like Descript.
3. Access resolution settings: Navigate to the video settings or export settings where you can choose a preset resolution.
4. Adjust the resolution:

1. For YouTube: If the original resolution exceeds 1080p, scale it down to 1920 pixels by 1080 pixels.
2. For general social media: Lower the resolution to 720p (1280 pixels by 720 pixels), which balances quality and file size well for mobile viewing.
3. For Instagram: Crop the video to a square format of 1080 pixels by 1080 pixels if it fits the content.

1. Export and save: Save your video and make sure the file size has been reduced to the level you want.

4. How to compress a video by reducing the bitrate

Reducing the bitrate is an easy way to reduce file size without shortening your video or changing the size of the image. However, it may not be the most intuitive fix unless you know what the ideal bitrate for your particular video resolution is. 

For videos that will be streamed online, like videos uploaded to YouTube, a good starting point is 8 Mbps for 1080p videos and 5 Mbps for 720p videos (at standard frame rates). 

Social media platforms usually have restrictions on how large video uploads can be, so 5 Mbps even for 1080p videos works well. You can play around with bitrate if the video is still too large—these numbers are just a jumping-off point. 

Here’s how to reduce the bitrate of a video: 

1. Identify the ideal bitrate: Determine the suitable bitrate for your video based on its resolution and the platform it’s designed for. For instance, 8 Mbps for 1080p and 5 Mbps for 720p videos are good starting points for online streaming.
2. Open your video editing software: Import your video file into a video editing program like Descript.
3. Navigate to the export, render, or share step in your software and locate the bitrate or video quality setting.
4. Adjust the bitrate: In user-friendly interfaces like Descript, you can select a video quality level such as low, medium, or high. In more advanced settings, type in the desired bitrate value.
5. Choose variable bitrate (VBR): If available, select the VBR option for a balance of video quality and file size.
6. Select encoding pass: If given a choice, opt for 2-pass encoding to improve video quality, though be prepared for a longer encoding time.
7. Export as an MP4 and save: Save the newly compressed video to your device and playback using your device’s media player to confirm the reduction in file size.

5. How to compress a video online

There are also online video converter services that allow you to compress video without the need for video editing software. Some require you to sign up for an account or pay for a subscription to compress longer videos while others are free. 

A few online video compression services worth considering are:

• Descript
• Online Converter
• Video Smaller
• Adobe
• Cloud Convert

Descript is one of the best video compressors out there. It makes it easy to compress video quickly.  Here’s how to resize and compress videos in just a few steps.

1. Prepare your MP4 files: Ensure you have the MP4 videos you want to compress. If you have videos in other file types like M4V, MPEG, and MOV, don't worry—Descript can handle these too.
2. Upload your videos to Descript: Launch Descript and upload your video files to the editing dashboard.
3. Edit your video (optional): Before compressing, seize the opportunity to edit your video if necessary. Trim unwanted parts or make other edits to shorten the video length, as a shorter video requires less encoding. Descript's automatic transcription feature simplifies editing, making it as easy as editing a document.
4. Compress your video: Click the Share button in Descript and Select Export. You'll now have the opportunity to set your video’s resolution and dimensions, either creating a new file or publishing it directly to YouTube.
5. Export and save: Once you’re satisfied with the settings, proceed to export your video. Save the compressed video to your device or share it directly to your preferred platform.

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How to compress a video on any device

The process for compressing a video can differ depending on the device you’re using. Below are steps tailored for Mac, Windows, and mobile devices like iPhone and Android—all of which help you reduce the video file size while maintaining decent video quality.

How to compress a video on Mac

Here’s how to use an Apple Mac device to compress video:

1. Locate your video file: Find the video file you want to compress on your computer. 
2. Open a video editor: iMovie and QuickTime Player are user-friendly options for basic video editing and compression tasks. For more advanced features, download the free Descript app for Mac.
3. Import your video: Add your video file to the editor and access the export settings.
4. Adjust compression settings: Customize the resolution, bitrate, and file format to reduce the video file size.
5. Export and save: Save the compressed video file to your desired location or share it directly to social media or other platforms.

How to compress a video on Windows

1. Locate your video file: Find the video file you want to compress on your device.
2. Open a video editor: Use your preferred video editor, like the free Descript app for Windows, to start the compression process. 
3. Import your video: Load your video file into the editor and navigate to the export or compression settings.
4. Adjust compression settings: Modify the resolution, bitrate, and encoding settings to achieve a smaller file size.
5. Export and save: Save the compressed video to your device or share it directly to platforms like YouTube or social media.

How to compress a video on iPhone and Android

If you don’t have a computer to compress video files, here’s how to do it from your smartphone. 

1. Locate your video file: Access the video file you want to compress on your device.
2. Download a video compressor app: Install a reputable video compressor app from the App Store or Google Play Store, such as Compress Videos & Resize Video (pictured below).
3. Open the app and import your video: Load your video file into the app and access the compression settings.
4. Adjust compression settings: Customize the resolution, bitrate, and other settings to reduce the video file size.
5. Save and share: Save the compressed video on your device or share it directly to social media or other platforms.

Want to join the thousands of creators already using Descript’s video editing software? Take a tour of the dashboard today.

How to compress a video FAQs

How do I reduce the file size of a video?

1. Change the video format
2. Trim the video
3. Reduce the video resolution
4. Reduce the bitrate
5. Use a free video compressor 

How do I compress a video so I can email it?

1. Use Descript’s free video compressor
2. Export the file as an MP4
3. Attach the video to your email 

How can I reduce the size of a video for free?

You can reduce the size of a video using free video editing and compression tools like Descript, or an open-source media player like VLC.