Works offline
119+ free tools · runs in your browser

Every file tool you need.
Nothing leaves your device.

Convert, compress, edit and share — 119+ free tools that run right in your browser. No uploads, no sign-up.

100% privateNo sign-upNo file limitsFree forever
video.mov → video.mp4Converted on this phone
0 KB uploaded · 0 KB downloaded
119+
free tools
7
categories
0
uploads, ever
100%
free & private

Popular right now

JSON FormatterPretty-print or validate JSONJWT DecoderInspect token claims offlineBase64 EncodeText ↔ Base64 in a clickRegex TesterLive matches as you typeTimestampsUnix ↔ human-readablePasswordsStrong, generated locallyShare filesSend between devices, no cloudCompress a photoShrink size, keep qualityMerge PDFsCombine files into oneVideo → MP4Play anywhereImage → JPGFrom PNG, WebP & moreQR codeFor any link or text

Browse by what you’re doing

Convert or trim audioMP3, WAV, FLAC & more6 tools
Trim AudioTo MP3To WAVTo M4ATo OGGTo FLAC

Guides

All guides →

Plain-language explainers for the problems behind the tools — certificate chains, HEIC photos, video codecs, PDF sizes, JWTs — written by the people who built them.

How it works12 min readHow on-device file tools work (and why nothing gets uploaded)What actually happens when you convert a file in your browser: WebAssembly engines, hardware codecs, memory limits, offline use, and how to verify for yourself that nothing leaves your device.Certificates & keys11 min readSSL certificate formats explained: PEM, DER, P7B, PFX and JKSA practical guide to every SSL/TLS certificate format — what each file contains, how to recognise it, which servers need which, and how to convert between them in your browser.Certificates & keys12 min readFix “certificate chain incomplete” and “unable to get local issuer certificate” errorsWhy a certificate works in Chrome but fails on phones, curl and Java: missing intermediates, wrong order, expired roots. How to diagnose each case and build a correct fullchain.pem.Images & photos11 min readJPG, PNG, WebP or HEIC? Choosing the right image formatA plain-language guide to image formats — lossy vs lossless, why screenshots hate JPG, what HEIC is, when WebP wins, and which format to pick for photos, logos, web pages and printing.Images & photos11 min readHEIC explained: why iPhone photos will not open on Windows, and how to convert themWhat HEIC/HEIF is, why Apple adopted it, why Windows, Android and many web forms reject it, the settings that stop your iPhone producing it, and how to convert batches to JPG without uploading them.Images & photos12 min readHow to compress images without visible quality loss: JPG quality, WebP and resizingWhere image bytes actually go, why resizing beats quality sliders, the JPG quality range that is invisible in practice, when WebP halves a file for free, and the settings to use for web, email and print.

Why OnMyDevice?

Every tool runs entirely in your browser — that one choice is where everything below comes from.

Privacy first

Files are processed by your own browser, never uploaded. There is no server that could leak, retain or sell your data.

Works offline

Once a tool loads, turn off Wi-Fi and it keeps working — proof that nothing leaves your device.

No file size limits

No 25 MB caps, no premium tiers. A 2 GB video converts the same as a 2 MB one — there is no upload at all.

Fast by design

Skipping the upload round-trip beats any server — 4K video converts in minutes using your device’s hardware.

Pro-grade engines

The same engines professionals use — FFmpeg, ImageMagick, pdf-lib — running safely inside your browser.

Free, no watermarks

Every tool is fully functional. No watermarks, no quotas, no “log in to download” tricks.

Kind to the planet

No data centers churning on your files — the device already in your hand does the work once, and nothing crosses the network.

Installs as an app

Add it to your home screen and it opens like a native app — with the same on-device guarantee.

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