Free File Converter: No Sign-up, No Upload, Files Stay on Your Device
This file converter is free, needs no sign-up or login, and your files never leave your browser. There is no upload, no watermark and no account. Drop in a photo, a song, a video, a document or a spreadsheet, choose the format you want, and the converted file is created on your own device.
It covers 13 kinds of file: images, audio, video, documents, e-books, presentations, vector graphics, fonts, subtitles, 3D models, spreadsheets, data files and archives. Each category has its own page with the exact formats it reads and writes, so you can see what is possible before you start.
Four things set it apart from a typical online converter. It runs in your browser instead of on a server. It converts a whole batch and hands the results back as one ZIP. It detects the format from the file content, so a wrongly named file is still recognised. And it shows options that fit the target format, such as image quality, a CSV delimiter or an audio bitrate.
- Free
- No sign-up
- Never uploaded
- No watermark
Your files are converted on your device and never uploaded.
Pick a converter
- Image ConverterConvert PNG, JPG, WebP, AVIF, HEIC, GIF, SVG and more between formats.PNG, JPEG, WebP, AVIF +18
- Audio ConverterConvert MP3, WAV, FLAC, AAC, OGG, M4A and more, or pull audio out of a video.MP3, WAV, OGG, Opus +15
- Video ConverterConvert MP4, WebM, MOV, MKV, AVI and more, make a GIF, or extract the audio.GIF, MP4, WebM, MOV +12
- Document ConverterConvert PDF, Word, ODT, RTF, Markdown, HTML and text files.PDF, Word (DOCX), OpenDocument Text (ODT), Rich Text Format (RTF) +4
- E-book ConverterConvert EPUB, MOBI, AZW3, FB2 and CBZ e-books to the format your reader needs.PDF, Markdown, HTML, Plain text (TXT) +5
- Presentation ConverterConvert PowerPoint and ODP slides to PDF, images or text.PDF, Markdown, Plain text (TXT), PowerPoint (PPTX) +1
- Vector ConverterConvert SVG, EPS, AI, PDF and DXF vector graphics, or trace a raster image.SVG, PDF, EPS, Adobe Illustrator (AI) +1
- Font ConverterConvert TTF, OTF, WOFF, WOFF2 and EOT fonts for the web or desktop.TrueType (TTF), OpenType (OTF), WOFF, WOFF2 +1
- Subtitle ConverterConvert SRT, VTT, ASS, SBV, LRC and other subtitle and caption files.Plain text (TXT), SubRip (SRT), WebVTT (VTT), Advanced SubStation Alpha (ASS) +7
- 3D Model ConverterConvert OBJ, STL, GLB, glTF, PLY and other 3D model files.Wavefront OBJ, STL (3D), GLB, glTF +7
- Spreadsheet ConverterConvert XLSX, XLS, ODS, CSV, TSV and other spreadsheet files.HTML, Plain text (TXT), Excel (XLSX), Excel macro-enabled (XLSM) +14
- Data ConverterConvert JSON, YAML, XML, TOML, CSV, INI and other data and config files.CSV, TSV, JSON, JSON Lines +11
- Archive ConverterConvert ZIP, 7Z, RAR, TAR, GZ and other archives between formats.ZIP, 7-Zip (7Z), RAR, TAR +11
How to convert
- Add your files by dragging them onto the page or by using the file picker, one or many at a time.
- Check the format detected for each file; it comes from the content, not only the extension.
- Choose the target format from the list of what that file can become.
- Adjust the options that appear for that format, such as quality, resolution or delimiter.
- Press Convert and watch each file finish.
- Download a single result directly, or the whole batch as one ZIP.
Features
- Thirteen categories: image, audio, video, document, e-book, presentation, vector, font, subtitle, 3D model, spreadsheet, data and archive.
- Runs in your browser: no upload, no sign-up, no watermark.
- Batch conversion with a single ZIP download.
- Format detection by file content, so renamed files are still recognised.
- Options for each format, shown only when they apply.
- Many pairs are converted by the page itself, with nothing to download.
- A few heavy pairs load a one-time engine, and the page shows its size first.
- Honest notes on what is lost: lossy formats, transparency, layout and styling.
About the formats
Images
The image converter reads PNG, JPEG, WebP, AVIF, JPEG XL, HEIC, GIF, APNG, BMP, ICO, CUR, TIFF, SVG, PSD, TGA, QOI, PCX, the Netpbm formats (PBM, PGM, PPM) and DNG. It writes most of them, except HEIC, CUR, PSD, PCX and DNG, which can be opened but not created. HEIC, the iPhone photo format, is usually converted to JPG so every app can open it.
JPEG is lossy and has no transparency, so transparent areas of a PNG become white. PNG is lossless and keeps transparency. WebP and AVIF are usually smaller at similar quality. Raster images can be traced to SVG, and any image can be placed into a PDF.
Audio and video
Audio formats include MP3, WAV, OGG, Opus, AAC, M4A, M4R ringtones, FLAC, ALAC, AIFF, AC3 and AMR. MP3, AAC, OGG and Opus are lossy; WAV, FLAC, ALAC and AIFF keep everything. Video formats include MP4, WebM, MOV, MKV, AVI, WMV, FLV, 3GP, OGV, MPEG and MPEG-TS, and a video can also become an animated GIF or WebP, or give up just its audio.
Your browser handles some audio and video pairs by itself. Others, such as WMV, FLV, AVI and GIF output, load the ffmpeg engine, an approximate 31 MB download that is kept by your browser after the first time. Only the engine is downloaded, never your video.
Documents, e-books and presentations
Documents cover PDF, Word (DOCX), OpenDocument Text, RTF, Markdown, HTML, plain text and LaTeX. E-books cover EPUB, FB2, MOBI, AZW3 and CBZ comic archives. Presentations cover PowerPoint (PPTX) and OpenDocument (ODP), which can become PDF, images or text.
These conversions keep text, headings, lists, tables and images, but complex layouts are simplified. A scanned PDF has no text to extract. MOBI and AZW3 can be read but not created, and a book protected by DRM cannot be converted at all.
Vector graphics, fonts and subtitles
Vector files include SVG, EPS, DXF and Adobe Illustrator (AI), which only opens when it holds PDF-compatible content. Fonts include TTF, OTF, WOFF, WOFF2 and EOT; WOFF2 needs a small engine of about 0.3 MB. Subtitles include SRT, VTT, ASS, SSA, SBV, SUB, LRC, TTML and SAMI, and EBU STL can be read.
Converting styled subtitles such as ASS to plain formats drops colours and positioning. Frame-based SUB files need the video frame rate to convert correctly.
3D models, spreadsheets, data and archives
3D models include OBJ, STL, GLB, glTF, PLY and USDZ output, and 3MF, FBX, Collada, OFF and 3DS as sources. STL keeps geometry only, so colours and textures are dropped. Spreadsheets include XLSX, XLS, XLSB, ODS, CSV and TSV, plus export to JSON, a Markdown table, SQL and PDF.
Data files include JSON, JSON Lines, YAML, XML, TOML, INI, ENV and Java properties. Archives include ZIP, 7Z, TAR and TAR.GZ, and RAR, XZ, ZST, CAB and ISO can be opened and repacked as ZIP. Reading 7Z, RAR and most other archive types loads a one-time engine of about 1.5 MB.
Lossy, lossless and what changes
Converting between lossy formats such as JPG to WebP or MP3 to AAC loses a little more each time, so convert from the original when you can. Converting a lossy file into a lossless format, such as JPG to PNG, makes a bigger file but does not bring back detail that is already gone.
Privacy: how it works
- Your files stay on your device. The page reads each file with the browser's file API, converts it with code running in the tab, and hands the result back as a download. No upload happens, so there is no copy of your file on our servers to protect, delete or leak.
- There is nothing to sign up for and no login. The converter does not ask for an email address, and it does not need to know who you are to do its job.
- Some conversions use a WebAssembly engine that your browser downloads once, the first time you need it. Only the engine is fetched, never your file, and the page shows the approximate size before it starts. Your browser caches it, so later conversions skip the download.
- You can check the claim yourself: open your browser developer tools, watch the Network tab while a file converts, and you will see no request that carries your file.
- Because the work happens on your device, speed and size limits depend on your own phone or computer, not on a server queue. Large videos and archives use your memory, so keep other heavy tabs closed when you convert them.
Tips
- Keep your original file and convert a copy, since lossy conversions cannot be undone.
- Pick the target by where the file will be used: JPG for photos, PNG for graphics, MP4 for video, MP3 for music, PDF for sharing.
- Use ZIP download when you convert more than a few files, so you get one file instead of many.
- Try a single file first when a pair is new to you, then run the whole batch.
- Close other heavy tabs before converting a long video or a large archive.
- Expect a one-time engine download for some video, audio, font and archive pairs, and let it finish.
- Check the format notes of the pair for what is kept and what is dropped.
- For documents, check the result for layout, since complex layouts are simplified.
- Convert HEIC photos to JPG when you need to share them with people using other devices.
Frequently asked questions
Is it really free?
Yes. There is no price, no trial, no credit card and no watermark added to your results. Ulkaa Tool does the conversion with your own device, so there is no server bill to pass on to you.
Are my files uploaded?
No. Your files are read and converted inside your browser and are never sent to Ulkaa or to anyone else. The result is created on your device and you save it from there. Some conversions load a small conversion engine the first time you use them. That download is the only network traffic, it contains no file of yours, and your browser keeps it for next time.
Do I need an account?
No. There is no sign-up and no login. Open the page, add your files and convert. An Ulkaa account is not needed for anything on this tool.
Is there a file size limit?
No limit is set by us. The real limit is your device: the conversion uses your own memory and processor, so very large files can be slow or fail on a weak phone or an older computer. Close other heavy tabs and convert files one at a time if a big batch struggles.