Private file tools

Everyday file tools that never upload your files

PDF, image, audio and video tools that run entirely on your device. Pick a tool, drop a file and download the result. No account, no upload.

Runs in your browser Free No sign-up

Quick picks

Audio & video

Convert, cut, compress and transcribe.

Video to MP3 Pick a video, choose MP3 (or WAV / M4A) and download the audio. The conversion runs on your computer or phone.
MP4 to MP3 MP4 is the most common video container; this page is tuned for it. Drop an .mp4 and get a clean 192 kbps MP3.
Video to text Drop a video you own; GustKit pulls the audio and runs Whisper on your device to produce a timestamped transcript and subtitles.
Audio to text Upload nothing. Open an MP3, WAV, M4A or voice memo and get an accurate, timestamped transcript in a few moments.
Audio converter Turn voice notes and recordings into MP3 (or M4A, WAV, OGG, FLAC) that play everywhere. The file is converted on your device and never uploaded.
Trim audio Play the file, mark the start and end, and download just that part. Great for ringtones, clips of a recording or the important bit of a voice note.
Compress video Shrink a phone video or screen recording so it fits in an email, a chat or an upload form. The video is re-encoded on your own device and nothing is uploaded.
Trim video Play the video, mark where it should start and end, and download the clip. Fast mode copies the streams in seconds, with no quality loss.
Video to GIF Choose the moment, how long it lasts and how big it should be. GustKit builds an optimised colour palette for a crisp GIF, right in your browser.
Remove audio from video Drop a video and download the same video without sound. The picture is copied as it is, so it takes seconds and the quality doesn't change.

PDF

Merge, split, compress and convert.

Images

Compress, resize and convert photos.

Files

Open and create ZIP archives.

Unzip & create ZIP Extract a ZIP on a phone, a Chromebook or a work computer where you can't install anything. Or pack several files into one ZIP to send them together.

How it works

Choose a file
Drop it on the page or pick it from your device. Nothing is sent anywhere.
Adjust if you want
Sensible defaults are already selected, so most tasks are one click.
Download the result
Processing happens in this browser tab, then you save the file.

How GustKit keeps your files private

Each tool loads a small engine into this tab: FFmpeg and Whisper compiled to WebAssembly for audio and video, pdf-lib and PDF.js for documents, the browser's own canvas for images. It then processes the file on your device.

There is no upload queue and nothing is stored on a server. Close the tab and the data is gone.

Frequently asked questions

Is GustKit really free?

Yes, every tool is free, with no sign-up. The only limits come from what a browser can handle (memory and processing time) and are shown next to each tool.

Which files work?

PDFs, common images (JPG, PNG, WebP, HEIC), most videos (MP4, MOV, MKV, WEBM) and audio files (MP3, WAV, M4A, OGG) that fit within the limits shown next to each tool.

Do I need to install anything?

No. Everything works in a modern browser on a computer or phone. Some engines download the first time you use a tool and are then cached by your browser.