About MBtoKB
A client-side image and PDF compression tool built around one idea: your files shouldn't have to leave your device to get smaller.
Our Mission
Most online compressors work the same way — you upload your photo or document to a remote server, wait while it's processed somewhere else, then download the result. That's slow, uses your data, and means a stranger's server briefly holds your signature, ID scan, or financial document.
MBtoKB does it differently. Every compression and conversion runs directly inside your browser using the HTML5 Canvas API and native client-side WebAssembly (WASM) — nothing is ever uploaded, because there's nothing to upload to. Your file goes from your device, through your browser's memory, back to your downloads folder. Nothing else touches it.
What We Built
Target Size Sizing
An MB to KB converter and image compressor that hits an exact target size, not just "smaller".
Advanced PDF Controls
A PDF compressor with both exact-size targeting and manual quality control.
Format Versatility
Support for 15+ image formats, so you're not stuck converting elsewhere first.
100% Free & Private
Zero uploads, zero accounts, zero cost. Everything processed directly in-browser.
Why It Matters
If you're compressing a passport photo, a signature, a tax document, or a resume, privacy isn't optional — it's the point. MBtoKB was built so you never have to choose between getting your file to the right size and keeping it private.