Compress
Reduce file size with smart compression. Target exact sizes for upload limits, or use quality presets for quick results. All processing happens locally in your browser.
About Compression
Quick Compress
Uses smart quality settings to reduce file size while maintaining visual quality. Best for most use cases.
Target Size
Set an exact file size limit. Perfect for platform upload limits (25MB email, 8MB Discord, etc.).
Web Streaming
Optimizes the file structure so videos start playing instantly when embedded on websites, instead of waiting to buffer.
How to Compress a Video Online
Compressing a video reduces its file size so it is easier to share, upload, or embed on a website. VidStudio makes the process straightforward with two compression modes and zero file uploads. Everything runs locally in your browser, so your video stays on your device from start to finish.
- Drop your video file. Drag any video onto the upload area or click to browse. VidStudio accepts MP4, MOV, AVI, MKV, WebM, FLV, and dozens of other container formats. There is no sign-up and no waiting for a server upload because the file never leaves your machine.
- Choose a compression mode. Quick mode lets you pick a quality percentage between 1 and 100. A setting of 70% works well for most videos, shrinking file size by roughly 40-60% with minimal visible difference. Target Size mode lets you type an exact output size in megabytes, such as 25 MB for a Gmail attachment. It uses two-pass encoding to hit that number accurately. You can also enable Web Streaming to move the MP4 moov atom to the front, so videos begin playing instantly when embedded on a web page.
- Download your compressed video. Click "Compress Video" and watch the progress bar. When it finishes, preview the output side-by-side with the original, check the file size comparison, and download the result as an MP4 file encoded with H.264.
Compression Modes Explained
Quick Mode
Set a quality value from 1% to 100%. The compressor maps this to an appropriate video bitrate automatically. Higher values preserve more detail; lower values produce smaller files. For everyday sharing, 60-80% strikes the best balance between quality and size.
Target Size Mode
Enter the exact file size you need in megabytes. The tool analyzes your video in a first pass, calculates the optimal bitrate, then encodes a second pass to land as close to the target as possible. Enable Fast mode for single-pass encoding when speed matters more than precision.
Web Streaming
When enabled, VidStudio moves the MP4 moov atom to the beginning of the file. This lets browsers start playback immediately rather than downloading the entire file first. Essential for any video you plan to embed on a website, especially if you care about Core Web Vitals and LCP scores.
Common Use Cases
Email Attachments
Gmail limits attachments to 25 MB, and Outlook caps them at 20 MB. Use Target Size mode to compress your video down to the exact limit so it arrives without bouncing back.
Discord
Free Discord accounts allow 8 MB file uploads, while Nitro subscribers get 25 MB. Enter 8 or 25 in Target Size mode to share clips in your server without hitting the wall.
WhatsApp limits video messages to 16 MB. Compress your clips to fit and they will send instantly instead of being rejected or re-encoded at lower quality by the app.
Social Media Uploads
Smaller files upload faster to Instagram, TikTok, YouTube, and LinkedIn. Compressing before uploading also prevents the platform from applying its own aggressive re-encoding.
Web Embedding
Large videos slow down page loads and hurt Core Web Vitals. Compress to a reasonable bitrate and enable Web Streaming so your pages stay fast and rank higher in search results.
100% Private: Your Video Never Leaves Your Device
Most online video compressors upload your file to a remote server, process it, and send it back. That round trip is slow, consumes bandwidth, and means a third party has access to your content. VidStudio takes a fundamentally different approach. It runs FFmpeg compiled to WebAssembly directly inside your browser tab. Your video file is read from disk into browser memory, processed there, and the result is saved back to your device. No network request is made, no data is transmitted, and no server ever sees your footage. This makes VidStudio ideal for confidential recordings, client work, unreleased content, or anything you would not want sitting on someone else's infrastructure.
Supported Formats
Input: MP4, MOV, AVI, MKV, WebM, FLV, OGG, M4V, WMV, 3GP, and most other video container formats. If FFmpeg can read it, VidStudio can compress it.
Output: MP4 with H.264 video encoding. H.264 is the most universally supported codec across browsers, phones, tablets, smart TVs, and media players. It delivers strong compression efficiency and is accepted by every major platform and messaging app.
Frequently Asked Questions
How do I compress a video without losing quality?
Set Quick mode to 70-80%. At these levels, VidStudio reduces bitrate in ways that are virtually invisible to the human eye while cutting file size significantly. If file size is critical, switch to Target Size mode and let the two-pass encoder find the best possible quality for your chosen limit.
What formats can I compress?
You can compress almost any video format: MP4, MOV, AVI, MKV, WebM, FLV, OGG, M4V, WMV, 3GP, and more. The output is always MP4 (H.264), which is compatible with virtually every device and platform.
Is it safe to compress videos online?
With VidStudio, absolutely. Your video is processed entirely inside your browser using FFmpeg WebAssembly. No file is uploaded to any server. Your footage never leaves your device, making this the safest way to compress a video online.
How long does compression take?
A typical 1-minute 1080p video compresses in 30-60 seconds in Quick mode. Target Size mode with two-pass encoding takes roughly twice as long. Longer or higher-resolution videos will take proportionally more time. Performance depends on your device CPU.
Is there a file size limit?
There is no enforced file size limit. Since all processing runs locally, the practical ceiling depends on your device's available memory. Most modern computers and phones handle videos up to several gigabytes without problems.
What is the difference between Quick mode and Target Size mode?
Quick mode sets a quality percentage and the encoder picks an appropriate bitrate. It is fast and works well when you do not need an exact output size. Target Size mode lets you specify a precise file size in MB and uses two-pass encoding to hit that target, which is ideal for platform upload limits.
Related Tools and Resources
Resize Video
Change video dimensions for any platform. Scale to exact pixel sizes or pick a standard aspect ratio like 16:9, 9:16, or 1:1.
Trim Video
Cut your video to the exact segment you need. Set start and end times to remove unwanted footage before or after sharing.
Normalize Audio
Fix uneven audio levels across your video. Normalize loudness so viewers do not have to adjust volume between clips.
How to Compress Video (Full Guide)
Read the complete tutorial covering compression theory, bitrate vs. quality tradeoffs, and step-by-step instructions for every mode.