動画圧縮ツール
WebCodecsハードウェアアクセラレーションによる超高速動画圧縮。DiscordやLINEの容量制限に合わせた目標MB指定が可能。透かし・制限なし。
or drag & drop here
Paste from clipboard with Cmd+V · Multiple files supported
Supported: MP4 · MOV · WebM
- Never uploaded
- No watermark
- No sign-up
- No server upload limits
How It Works
Simple 3-step compression powered entirely by your local browser
動画ファイルを選択
MP4, MOV, WebMに対応。サーバーへのアップロード待ちはなく、端末内で即時読み込み。
目標MBまたはバランスを指定
DiscordやLINEの容量制限に合わせたMB指定、または画質重視のバランスモードを選択。
ハードウェア高速エンコード
WebCodecsを活用してGPU/CPUで高速圧縮。透かしなしで標準MP4を出力。
Why Choose LessMB
The private, modern alternative to legacy cloud compressor websites
100% In-Browser Privacy
Zero bytes uploaded. Your personal photos, sensitive documents, and private videos never touch external servers or cloud storage.
Zero Queue & Instant Start
No waiting in cloud conversion queues or watching slow upload bars. Processing starts the millisecond you drop your file.
Hardware Acceleration
Harnesses WebAssembly SIMD and WebCodecs GPU encoding for high-fidelity compression directly on modern consumer hardware.
No Credit Consumption
Free tier compression uses your own device compute, meaning zero server credit drain for everyday single and batch tasks.
LessMB vs Traditional Cloud Compressors
See how client-side processing outperforms legacy server-based tools
Specialized Tools & Guides
Purpose-built browser tools solving specific format and platform constraints.
HandBrake Online Alternative
A fast, zero-install HandBrake alternative for video compression. Uses WebCodecs hardware encoding directly on your GPU without complex settings.
Compress Video for Discord
Compress videos locally for Discord. Choose a target below your account limit, including the default free 20MB cap, and inspect the result before sharing.
Compress Video for Email
Compress video for email locally. Choose a target below your Gmail, Outlook, or work account limit, then check file size and playback before attaching.
動画の目標容量と推奨ビットレート換算表
動画の再生時間と目標容量（Discord 10MB、LINE・メール 20MB）に応じた最適な解像度とビットレートの目安です。
| 再生時間 | 目標サイズ | 解像度 | 映像レート | 音声レート | 主な対象サービス |
|---|---|---|---|---|---|
| 30s | 8 MB | 1080p (1920x1080) | ~2,050 kbps | 128 kbps | Discord 8MB 制限 |
| 60s | 10 MB | 1080p (1920x1080) | ~1,240 kbps | 128 kbps | Discord 無料版の上限 |
| 60s | 25 MB | 1080p (1920x1080) | ~3,280 kbps | 128 kbps | LINE動画・Gmail・Outlook |
| 120s (2 min) | 25 MB | 720p (1280x720) | ~1,580 kbps | 128 kbps | チュートリアル録画・ミーティング共有 |
| 180s (3 min) | 25 MB | 720p (1280x720) | ~1,010 kbps | 96 kbps | スマホ間での動画シェア |
Frequently Asked Questions
Everything you need to know about LessMB in-browser compression
Looking for other file formats? Back to LessMB Free Online File Compressor