Smart Video Compressor
Shrink heavy MP4, WebM, and MOV video files by up to 90% right in your browser. Optimized presets for WhatsApp, Discord 8MB file limits, and email attachments. 100% private: zero bytes ever leave your device.
Drop any video to shrink file size or select targeted sharing presets
Drop your video here, or click to browse
Instant local compression. Zero wait times. Files automatically deleted from memory.
Instant video compression without cloud uploads.
No account required, no server uploads, no queue delays. Every frame render and compression pipeline happens directly inside your web browser.
Load Your Video
Drag & drop any MP4, WebM, MOV, M4V, or MKV video. The browser immediately reads dimensions, aspect ratio, duration, and audio streams in memory without data transmission.
Pick Preset or Target Size
Select WhatsApp 720p, Discord 8MB auto-limit, or Email 25MB ceiling. The dynamic calculator projects your compressed file weight and percentage savings in real time.
Encode & Instant Download
Hardware-accelerated encoding renders frames locally on your GPU/CPU. Download your compressed video instantly. Files auto-delete from memory when the tab closes.
Video upload caps & recommended bitrates.
Reference upload size ceilings, recommended aspect ratios, and optimal bitrates for every major platform.
| Platform | Max File Cap | Recommended Resolution | Ideal Bitrate | Calkora Preset |
|---|---|---|---|---|
| Discord (Free) | 8 MB | 720p / 480p | 600 – 900 kbps | 💬 Discord (< 8MB) |
| WhatsApp Media | 16 MB | 720p / 1080p | 1.0 – 1.5 Mbps | 📱 WhatsApp & Chat |
| Gmail / Outlook Attach | 25 MB | 720p HD | 1.5 – 2.0 Mbps | 📧 Email (< 25MB) |
| Instagram Reels & Stories | 4 GB | 1080 × 1920 (9:16 Vertical) | 3.5 – 5.0 Mbps | 🌐 Web & Social (1080p) |
| X (Twitter) Feed | 512 MB | 1080p / 720p | 2.5 – 4.0 Mbps | 🌐 Web & Social (1080p) |
| YouTube Shorts & Videos | 128 GB | 1080p / 4K Ultra HD | 8.0 – 15.0 Mbps | 🌐 Web & Social (1080p) |
Got questions? We've got answers.
🔒 Are my videos uploaded, and when are converted files deleted?
Zero video bytes or metadata are ever uploaded to any server. All processing runs entirely inside your device's local browser RAM using HTML5 Canvas and browser media codecs. Converted files and temporary frames are automatically deleted after closing or refreshing this tab. You can also purge memory at any time by clicking the “Clear” button in the header.
💬 How does the Discord 8MB auto-cap preset work?
When you select the “Discord (< 8 MB)” preset, Calkora inspects your video's exact duration in seconds, calculates a safety margin allowance for audio, and auto-tunes the target video bitrate to guarantee the final encoded file stays strictly below Discord's 8MB upload cap.
⚡ Why is in-browser compression so fast?
Traditional converters require you to upload your large 100MB+ file across the internet to a server, wait in a processing queue, and then download it back. Calkora leverages your device's native GPU and CPU via the browser's hardware-accelerated MediaStream API with zero network lag or queue time.
🔊 Can I preserve or mute the audio track?
Yes. By default, your original audio stream is preserved and mixed cleanly at 96 kbps. If you are sharing a clip that does not require sound, simply toggle the “Include Audio Track” switch off to mute the video and unlock even greater file size reductions.
📦 Which output format will I download?
Calkora automatically matches your input file type: uploading an MP4 defaults to an MP4 download, and WebM defaults to WebM. You can switch between .MP4 (universal compatibility across iPhones, iPads, and Android) and .WEBM (modern high-compression web format) in one click before compressing.