S Converter
The free, offline file converter for Windows 11 and 10.
HEIC to JPG, video to MP4 or MP3, Word to PDF, photos under 100 KB, PDF tools and password ZIPs: fast, beautiful, and completely offline. No upload, no watermark, no limits.
Contents
Why S Converter
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|---|
| 🔒 Private | Everything happens on your own PC. Nothing is uploaded, ever, and it works with no internet connection. |
| ⚡ Fast | Converts whole folders at once and uses your graphics card for video. |
| 🧰 All in one | Images, video, audio, documents, PDFs and archives in a single app, with no extra software to install. |
| 🎯 Two clicks | Select files in File Explorer, press a shortcut, pick a format. Done. |
| ✨ Beautiful | A modern interface with four themes, from soft glass to classic chrome. |
| 💸 Free | No ads, no watermark on your files, no account, no limits. |
Features
Convert anything, in batches
Drop in one file or hundreds. Pick the output format, adjust the quality if you like, and press Convert. One-click presets handle everyday jobs such as Email, Instagram, Web and Thumbnail.
When it's finished you see exactly what was made and how much space you saved, with one click to open each file or its folder.
Make it fit: size limits and form photos
Upload forms say under 100 KB, email stops at 20 MB. Switch Quality to Max size, pick the limit, and S Converter finds the best quality that fits.
- Photos under 100 KB, 200 KB, 1 MB or any limit you type; videos under 20 MB for email, 16 MB for WhatsApp
- Form photo: US visa (600 × 600 px, under 240 KB), passport 35 × 45 mm, 2 × 2 inch, or your own size, cropped around the face
- Recipes: save a preset that converts, renames and packs everything into one ZIP or PDF
How it works →
Quick Convert, right from File Explorer
Select files in File Explorer, on the desktop or in any Open or Save dialog and press Ctrl + Alt + C, or right-click them and choose S Converter → Quick Convert…. A wheel opens right at your mouse: point at a format and click. The app doesn't even need to open.
- Formats and Presets pages, with presets like Email, WhatsApp, Make GIF, Get Audio and Locked ZIP
- Several photos to PDF asks whether you want one PDF or one per photo
- Keyboard friendly: numbers pick a slice, Tab switches pages, Esc closes
- Drag the wheel anywhere by its centre
- Works on folders too: pack them into ZIP, 7Z or RAR in one go
- Paste as…: with nothing selected, it converts the image on the clipboard and copies the result back
- Several photos to one PDF opens a Page order screen, so the pages come out the way you want
Video, with your graphics card
Convert between MP4, MKV, MOV, WebM, AVI and more, make GIFs, pull out the audio, change the resolution, and trim clips with a visual timeline. S Converter detects NVIDIA, Intel and AMD graphics and uses them automatically for much faster encoding, falling back to the processor whenever needed.
Documents, no Office needed
Word, PowerPoint, Excel, OpenDocument, RTF, Markdown, HTML, EPUB and plain text, converted by S Converter's own engine, with no Microsoft Office or LibreOffice required.
- Word and OpenDocument keep headings, bold and italic, lists, tables, pictures and links
- PowerPoint slides become a PDF that keeps their layout, pictures and colours
- Tables inside a document can become an Excel spreadsheet
- PDFs get A4 pages with page numbers
PDF tools
Everything you usually need an online PDF site for, done privately on your PC:
| Tool | What it does |
|---|
| Images → PDF | One PDF from many pictures, or one PDF per picture |
| PDF → Images | Every page as a JPG |
| Merge | Join PDFs, in the order you choose |
| Split | Every page on its own, or by ranges like 1-3, 4-8, 9- |
| Compress | Make PDFs smaller while keeping text sharp |
| Rotate | Turn every page |
| Page numbers | Add "Page 1 of 9" and similar |
| Extract pages | Keep only the pages you pick |
Watermarks
Add your name or logo to photos and videos. Drag it where you want it on a live preview, then set size, colour and opacity, add a background box, repeat it in five places so it's harder to crop out, or let it scroll across a video. The same watermark is applied to every file in the batch.
Archives and passwords
- Pack folders into ZIP, 7Z, RAR or TAR.GZ
- Protect them with a password: ZIP uses AES-256 encryption; 7Z (with 7-Zip) and RAR (with WinRAR) hide the file names as well
- Extract ZIP, 7Z, RAR, TAR, ISO and CAB files, including password-protected ones, without the pointless extra folder
Four themes
Pick the look you like in Settings → Theme. The Quick Convert wheel changes with it.
Documentation
The full user guide is in docs/ and on the website:
Install and update · Convert files · Quick Convert wheel · Right-click menu · Presets and recipes · Keyboard shortcuts · Make it fit · Trim, watermark and rename · PDF tools · Archives · Watch folders and history · Privacy · Settings · Supported formats · Troubleshooting
Supported formats
| Category | Converts from | Converts to |
|---|
| Images | JPG, PNG, WebP, AVIF, TIFF, GIF, BMP, SVG, HEIC/HEIF (iPhone), camera RAW (CR2, NEF, ARW, DNG, RAF, ORF, RW2) | JPG, PNG, WebP, AVIF, TIFF, GIF, PDF |
| Video | MP4, MKV, AVI, MOV, WMV, FLV, WebM, MPEG, M4V, 3GP, TS, VOB, MTS/M2TS, OGV | MP4, MKV, AVI, MOV, WebM, GIF, WMV, FLV, MPEG, 3GP, TS |
| Audio | MP3, WAV, FLAC, AAC, OGG, WMA, M4A, AIFF, Opus, AMR, AC3, and the sound from any video | MP3, WAV, FLAC, AAC, OGG, M4A, Opus, AIFF, WMA, AC3, AMR |
| Documents | DOCX, DOC, ODT, RTF, TXT, Markdown, HTML, EPUB, PPTX, PPT, ODP, XLSX, XLS, ODS, CSV | PDF, DOCX, ODT, RTF, HTML, TXT, Markdown, XLSX |
| Archives | ZIP, 7Z, RAR, TAR, TGZ, GZ, BZ2, XZ, ISO, CAB | Folder, ZIP, 7Z, RAR*, TAR.GZ |
* Creating RAR files needs WinRAR installed. Password-protected 7Z needs 7-Zip.
Install
- Download the installer: open the latest release and click S-Converter-Setup-x.x.x.exe under Assets.
- Run it. Windows may show "Windows protected your PC". Click More info, then Run anyway. This happens because the installer isn't code-signed yet; it doesn't mean anything is wrong with the file. Prefer no warning? Get S Converter from the Microsoft Store instead.
- Choose where to install. No administrator rights are needed.
- Open S Converter from the Start menu or the desktop shortcut, and drop in some files.
To turn on the right-click menu in File Explorer, open Settings and switch on Explorer right-click menu. On Windows 11 it appears under Show more options.
Updates
S Converter keeps itself up to date automatically. It downloads new versions in the background and installs them on its own when you're not using it, never in the middle of a conversion, then carries on exactly where it was. There's nothing to click. You can see the current version, or check right away, in Settings → Updates.
See what changed in each version on the Releases page.
Frequently asked questions
Requirements
- Windows 10 (version 1809 or newer) or Windows 11, 64-bit
- About 600 MB of free disk space
- Optional: an NVIDIA, Intel or AMD graphics card for faster video; WinRAR to create RAR files; 7-Zip for password-protected 7Z
Feedback
Found a problem or have an idea? Open an issue and include what you were converting, what happened, and your Windows version.
S Converter is developed by Sujith Shalitha Dassanayake.
© 2026 Sujith Shalitha Dassanayake. All rights reserved. Free to download and use.
