About this tool
Image compression reduces file size by removing detail your eyes do not notice. The two main algorithms are lossy (JPG, WebP) and lossless (PNG). Lossy compression with a quality slider gets you the most savings - typically 60-90% smaller - while keeping the image visually identical to the source. Lossless compression usually saves 10-30%.
This tool compresses in your browser via Canvas re-encoding. Drag the quality slider to find the sweet spot for your image: photos with lots of detail tolerate quality 70-85; flat-color graphics, screenshots, and logos stay sharper at quality 85-95. Below 60 you start to see banding and JPG block artifacts; above 95 the file size grows without visible quality gain.
How it works
Open the image
Drop or pick a JPG, PNG, or WebP. The current file size is shown.
Pick output format
JPG for photos, PNG for screenshots/logos, WebP for the smallest file at any given quality (modern browsers).
Drag the quality slider
Start at 80. Watch the live preview and the new file-size readout. For photos drop to 60-70; for graphics keep 85-95.
Download the compressed file
Save to your device. Compare the file sizes side-by-side; usually 60-90% smaller.
Use cases
Web performance
Page-weight is the largest single Core Web Vitals factor. Compressing hero images alone often shaves 1-3 seconds off Largest Contentful Paint.
Email and chat attachments
Outlook and Gmail cap attachments. A 5 MB photo at quality 75 becomes a 700 KB photo - same look, fits 7x more in one email.
Storage savings
10,000 photos at 5 MB each is 50 GB. Compressed to 1 MB each is 10 GB - your phone backup, iCloud, Drive bills all drop accordingly.
Print proofing
Send a quality-30 preview to a client to verify framing before transferring the full-size file.
Format and spec details
| JPG quality range | 0-100, sweet spot 70-85 for photos |
|---|---|
| WebP at equivalent quality | ~25-35% smaller than JPG |
| PNG compression | Lossless palette + filtering, typical 10-30% reduction |
| Output format | JPG / WebP for lossy, PNG for lossless |
Tips and best practices
- Convert to WebP for the web - it is the single biggest free win on page weight.
- Compress the source, not a re-export of an already-compressed file. Loss compounds.
- For thumbnails, drop to quality 65 - users will not notice on a 200x200 preview.
- PNG screenshots compress much better as PNG than JPG - JPG artifacts on text are very visible.
How to use the Image Compressor
The Image Compressor is a browser-based tool that runs entirely on your device. Inputs you enter never reach a server - all calculations happen client-side in JavaScript. This means:
- Privacy: nothing is logged, sent, or stored by 3Tej. Inputs disappear when you close the tab.
- Speed: results update as you type. No network round trip.
- Offline use: once the page is cached, it works without internet.
- No signup: no account, no email, no rate limits.
Step by step
- Enter your inputs in the form above. Each field is labeled with its unit (currency, percent, kg, etc.) and the expected range.
- Read the result as it updates. The number reflects the formula commonly accepted in Image Compressor-related calculations.
- Adjust to see sensitivity: change one input at a time and watch how the output moves. This is the fastest way to understand which variable matters most.
- Copy or screenshot the result for later reference. The page state persists for the session if your browser allows it.
When you would use this
- Quick estimates: when you need a number now and don't want to open a spreadsheet.
- Sensitivity analysis: testing how a result changes as inputs vary, before committing to a real-world decision.
- Comparison: running the same calculation with different inputs to compare options side by side.
- Learning: building intuition for how the underlying math behaves.
- Documentation: capturing a snapshot of inputs and outputs at a point in time.
Privacy and offline operation
Every operation in this tool runs client-side using your browser's built-in APIs (Canvas, Web Audio, WebAssembly). No data is uploaded. After the initial page load you can disconnect from the internet and the tool keeps working.
We use Google Analytics and AdSense for the page itself, but neither sees the content of the files you process.
Frequently asked questions
What quality should I use?
Photos: 75-85. Graphics / screenshots: 85-95. Anything below 60 starts to show JPG block artifacts visibly. Test on the most detailed area of your image.
Is WebP really 30% smaller than JPG?
On average, yes. WebP's newer compression handles smooth gradients and large flat areas better. Browser support is excellent (Chrome, Edge, Safari, Firefox, even Internet Explorer 11 via fallback).
Will compressing a JPG twice double the loss?
Yes - JPG compression is lossy and stacking compression rounds adds artifacts. Always compress from the original, never from a previously-compressed JPG.
Does compression remove EXIF metadata?
This tool strips EXIF on save, including GPS and camera model. To preserve metadata after compression, use a dedicated tool like exiftool.
What is "near-lossless" PNG?
A PNG-8 (palette) version of the source with only 256 colors selected. Works great for screenshots and graphics, less well for photos.
Is the Image Compressor accurate?
The Image Compressor applies the standard formula for image compressor. Accuracy is limited only by your input precision. For decisions with material consequences, use the result as a starting point and verify with a qualified professional or the relevant official source.
Is the Image Compressor free?
Yes. 100% free, no signup, no payment, no API key. The site is funded by display ads that appear around the tool but not inside the calculation flow.
Are my inputs saved?
No. Inputs stay in your browser tab. Closing the tab discards them. The site uses Google Analytics for traffic measurement (anonymized) but does not see what you type into the form.
Can I use the Image Compressor on my phone?
Yes. The tool is responsive and tested on iOS Safari, Android Chrome, and major desktop browsers. Touch targets meet Apple's 44pt and Google's 48dp minimum guidance.
How do I report a bug or suggest improvement to the Image Compressor?
Email hi@3tej.com with the URL of this page and a description of what you saw vs expected. We typically respond within 72 hours and update calculators when rules or formulas change.
How accurate is the Image Compressor?
It applies the standard formula. Accuracy is limited only by your input precision. For decisions with material consequences (taxes, medical, legal, structural), use the result as a starting point and verify with a qualified professional in the relevant field.
Is the Image Compressor free to use?
Yes. 100% free, no signup, no payment, no API key. The site is funded by display ads around the tool but not inside the calculation flow.
Are my inputs saved anywhere?
No. All inputs stay in your browser tab. Closing the tab discards them. The site uses Google Analytics for traffic measurement (anonymized) but the analytics never see what you type into the form.
Does the Image Compressor work offline?
Yes. Once the page has loaded, it works without internet. The calculation runs in JavaScript on your device.
Can I share results from the Image Compressor?
Take a screenshot or copy the output. The page doesn't generate shareable URLs for specific calculations - inputs stay in your browser only.
Why are the results different from another image compressor tool?
Most likely: different formula assumptions, different default values, different rounding rules, or different applicable rates. Check the methodology if both tools document it. Both can be valid for different scenarios.