Email and messaging
Bring a recording under an attachment limit while keeping enough detail for viewing on common screens.
Video Compressor
Reduce video size for sharing, uploading or storage with quick target-size presets and advanced controls.
Target-size modeAdvanced controlsLocal file processing
Read the full guideDrop a video here
or click to choose a file
Supported formats: MP4, WebM, MOV, MKV
Maximum file size: 2 GB
5 MB10 MB20 MB50 MB100 MB
Original video
Add a video
Compressed estimate
Preview size and quality are estimates until the full encode finishes.
1280px~10.0 MBavc
How can I make a video file smaller?
Add a video, choose a target file size or adjust resolution, codec, frame rate and audio, then compress and download the result. Lower resolution and bitrate usually reduce size most, while every re-encode can affect visual quality.
Video compression in one sentence
Video compression reduces file size by re-encoding picture and audio with a lower data rate, smaller frame, different codec or fewer frames per second; the best settings depend on where the video will be used.
When video compression is useful
Website and CMS uploads
Create a lighter delivery copy so pages and media libraries are easier to manage. Keep the original master separately.
Course and meeting recordings
Reduce large screen recordings by choosing a practical resolution and frame rate for mostly static content.
Archive and backup copies
Make access copies for quick review while preserving important source footage in its original format.
How to compress a video
Add the source video
Choose a file from your device or use a public direct URL that the browser is allowed to read.
Choose basic or advanced mode
Use target-size mode for a quick result. Use advanced mode when resolution, bitrate, codec or FPS must be controlled explicitly.
Check the estimate
Review the expected size and warnings. If quality looks risky, increase the target size or reduce less aggressively.
Run the compression
Keep the tab open while the browser decodes, re-encodes and builds the output file.
Review and download
Compare size and playback, then download the result before refreshing the page. Keep the original when it may be needed later.
Choose compression settings that match the job
Target size is an estimate
A target-size workflow calculates a bitrate from duration and reserved audio data. Motion, noise, encoder behavior and container overhead mean the final result can differ.
Resolution versus bitrate
High resolution with very low bitrate often looks soft or blocky. If the target is strict, a smaller frame can look cleaner than keeping full resolution at insufficient bitrate.
Choose codecs by compatibility
Newer codecs may compress efficiently but are not guaranteed to encode or play everywhere. Capability detection and the destination platform should determine the choice.
Audio can matter
For long videos with a small target, audio bitrate can consume a meaningful share. Remove audio only when it is genuinely unnecessary, or lower its bitrate while checking speech clarity.
Do not upscale quality
Compression creates a delivery copy; it cannot restore detail missing from the source. Avoid enlarging low-resolution footage unless a destination explicitly requires those pixel dimensions.
Privacy and processing
A file chosen from your device is processed in the current browser session and is not uploaded to AppKiro by this tool. A remote URL must be fetched from its source host, and the generated result remains temporary until you download it.
Important limitations
- The final file may not match the target size exactly.
- Encoding speed depends on duration, resolution, codec, hardware and browser implementation.
- A 2 GB picker limit does not guarantee that every 2 GB video fits in browser memory.
- Codec and container availability varies by browser and operating system.
- Refreshing or closing the page can discard an undownloaded result.
Video compressor questions
Are local videos uploaded to AppKiro?
No. A file selected from your device is processed in the current browser. URL mode is different because the browser must contact the source server to retrieve the video.
Will the compressed file hit my target size exactly?
Not always. The tool estimates a bitrate from duration and settings, but scene complexity, encoder behavior and container overhead affect the final size.
Why can the compressed video be larger?
The source may already be efficiently compressed, or the selected bitrate, resolution, codec and audio settings may require more data. Use a lower bitrate or resolution and compare again.
Which setting reduces size the most?
Video bitrate and resolution usually have the largest effect. Duration, frame rate and audio also matter. Change one factor at a time and inspect the result on the screen where it will be viewed.
Does a newer codec always give a smaller file?
No. Results depend on the encoder, source content and settings, and compatibility may be narrower. Choose a codec that the browser can encode and the destination can play.
Why is compression slow?
The browser must decode and re-encode many frames. Long duration, high resolution, complex codecs and limited hardware increase processing time.
Can compression improve poor video quality?
No. Compression cannot recreate detail missing from the source. It can only make a new copy with different size and encoding trade-offs.
What happens if the browser runs out of memory?
Processing stops and no usable output may be produced. Try a shorter clip, lower resolution or smaller source, close other heavy tabs, and run the job again.