File Compressor Online: Pick the Right Tool by File Type
Last reviewed 2026-05-08. Every tool linked from this page runs in your browser - your file is processed locally on your device, no signup required.
Pick a tool by what you have
| What you have | What to do | Tool | Typical size cut |
|---|---|---|---|
| A folder of mixed files (documents + photos + spreadsheets) | Make a ZIP archive | Zip File | 20-50% on text-heavy folders; 1-3% on media-heavy folders |
| Loose JPG / PNG photos | Lower the JPEG quality | Compress Image | 30-70% at quality 60-80 with no obvious quality loss |
| iPhone HEIC photos that must open on Windows / Android | Convert HEIC to JPG | HEIC to JPG | compatibility win; size similar to slightly smaller |
| Several images going to one recipient | Bundle them into one PDF | Images to PDF | 0-20% vs separate (one file is easier to send) |
| Several PDFs going to one recipient | Merge into one PDF | Compose PDF | 5-15% from de-duplicated headers and metadata |
ZIP a folder of mixed files
The Zip File tool bundles every file in a folder into one .zip archive and offers it as a download. The archive runs DEFLATE compression on the byte stream, so text-heavy folders (documents, source code, CSV) shrink 20-50% while media-heavy folders (JPG / PNG / MP3 / MP4) shrink only 1-3% because those formats are already internally compressed. The whole job runs locally in the browser - no upload to any server - and a password option is available when sharing sensitive content.
If a ZIP comes out larger than the upload limit (most often when the folder is photo-heavy), the right move is "compress the photos first, then ZIP the folder". Use Compress Image on the photos before adding them to the archive.
Compress JPG and PNG photos
Compress Image lowers the JPEG quality on a photo to reduce file size while keeping the resolution unchanged. At quality 60-80 most photos shrink 30-70% with no visible loss; at quality below 50 the change becomes noticeable on faces and skies. PNG photos with photographic content can also be re-encoded to JPG for additional savings, while PNG screenshots and logos with text or sharp edges should stay as PNG to avoid compression artifacts.
Convert iPhone HEIC photos to JPG
HEIC is the default photo format on iPhone since iOS 11 and is not natively supported on older Windows or Android devices. HEIC to JPG converts the file so the recipient can open it without installing a HEIC plugin. The byte savings are small - HEIC is already a modern, efficient format - but the compatibility win is the point: the photo opens cleanly on every modern device after conversion.
Bundle several images into one PDF
Images to PDF takes a stack of JPG or PNG files and outputs one PDF with one image per page. Recipients see the photos in order without needing to download a folder; they scroll through the PDF instead of opening each image separately. The output is roughly the same total size as the input - PDF does not re-compress photos by default - but one attachment is easier to send than ten.
Merge several PDFs into one
Compose PDF merges multiple PDFs into a single document. The output preserves the original page content but de-duplicates document-level metadata and shared font tables, so the merged file is typically 5-15% smaller than the sum of the inputs. The page order matches the upload order; rearrange the inputs before merging if needed.
Why "file compressor" is not a single tool
People searching for a "file compressor" arrive with different inputs and different goals: a folder of receipts going into Gmail's 25 MB attachment limit, a stack of iPhone photos that need to open on a Windows desktop, a 4K video that has to fit a Slack DM, twelve scanned PDFs the lawyer asked for as one file. The naive answer - "use a free file compressor" - hands every user the same tool, and most of them get a worse outcome than if they had picked the right specialist for their input. The decision table at the top of this page maps each input shape to the right tool in one click.
The reason there is no single universal compressor is that the underlying compression math is different for each file type. ZIP-ing a folder of JPGs saves almost nothing because JPG is already compressed. Image compression does not help a folder structure. Video re-encoding cannot run on a 4 GB file in a browser tab. Converting HEIC to JPG is about device compatibility, not byte savings. The five tools listed here each beat a generic "file compressor" for their specific case - and they all run locally in your browser, no signup, no upload to a remote host.
How privacy works in this browser file compressor toolset
Every tool linked from this page runs entirely in your browser. Files are read from your device, processed in tab memory, and the result is offered as a download. Nothing is uploaded to a remote server, no account is required, and the browser does not retain the input or output once you close the tab. That makes the toolset safe for contracts, medical records, payslips, and other documents you do not want to copy onto a third-party host.
When a single very large file does not fit any compressor
If the input is one very large file - a 4K video, a RAW photo, a design source over 1 GB - no in-browser compressor will help much. Video re-encoding to a smaller bitrate is the right move and is best done by a desktop tool (HandBrake on Windows / macOS / Linux is free) rather than a browser tab, because browser memory limits stop large encodes mid-way. RAW photos and design sources are usually best transferred via a file-share link (Google Drive, Dropbox, WeTransfer) instead of compressed.
FAQ
What is the best free file compressor for a folder?
For a folder of mixed files going to email, Zip File is the right pick. ZIP is the default archive format on Windows, macOS, Linux, iOS, and Android, so the recipient does not need any extra software to open it. The DEFLATE compression saves 20-50% on text-heavy folders.
How do I compress a JPG without losing quality?
Use Compress Image at quality 70-80. At that range the file shrinks 30-50% with no visible loss on most photos. Below quality 50 the loss becomes visible on skin tones and skies. The tool keeps the original resolution and does the encoding locally in the browser.
Why are my ZIP files barely smaller than the input folder?
ZIP applies DEFLATE compression on the byte stream, but DEFLATE cannot squeeze formats that are already internally compressed. JPG, PNG, MP3, MP4, MOV, and most modern document formats are already compressed, so a ZIP of those files saves only 1-3%. To shrink further, compress the photos first with Compress Image, then ZIP the folder.
Does compressing a file remove its metadata?
ZIP preserves file metadata (timestamps, names, directory structure). Image compression preserves EXIF metadata by default, which on phone photos includes the GPS coordinates the photo was taken at - if you are uploading the photo somewhere public, strip EXIF first. PDF compression preserves the document text but may rewrite annotations.
Is this file compressor really free?
Yes. Every tool linked from this page is free and runs in your browser without an account. There is no upload limit beyond what your device's memory allows, no watermark on the output, and no signup. The site is funded by AdSense, not by selling your files or your data.