Compress a JPG to 300 KB with almost no visible loss
300 KB is a generous budget. It's enough to keep a phone photo large, sharp, and detailed while cutting its size by 80 to 95 percent. That makes it a common limit for listing photos on marketplaces and real estate sites, document uploads on application and government portals, contest and gallery submissions, newsletter images, and photos you want to email to a group without clogging inboxes. This tool gets any image under 300 KB, or any size you choose, and spends nearly every allowed byte on detail.
Nothing is uploaded. The image is decoded, resized, and compressed by your own browser.
How to use it
- Choose one or more images, or drop them onto the box. JPG, PNG, WebP, GIF, BMP, and AVIF all work, and each result is saved as a JPG.
- Keep the 300 KB target, pick 200, 400, or 500 KB, or type your own.
- Leave Longest side on "No limit" to keep as much resolution as possible, or cap it to the size you'll actually display.
- Enter an exact width and height only if a form asks for specific pixel dimensions.
- Hold Hold to compare to check the result against the original, then download one image or the whole batch as a ZIP.
What a 300 KB JPG can hold
At 300 KB, most photos keep far more resolution than a screen can show. Rough figures for a typical photo at high quality:
| Kind of image | Longest side at 300 KB, roughly | Prints sharply at 300 DPI up to |
|---|---|---|
| Busy photo (trees, crowds, textures) | 1,600 to 2,200 px | About 5 × 7 in |
| Everyday photo (people, rooms, products) | 2,200 to 3,000 px | About 6 × 8 in |
| Portrait or product on a plain background | 3,000 px or more | About 8 × 10 in |
| Scanned document page | 2,500 to 3,500 px | A full letter or A4 page at 300 DPI |
These are estimates. Every picture compresses differently, so the tool measures the real result instead of guessing, and each card shows how large the image would print.
300 KB vs. 300 DPI
These two numbers get mixed up constantly, but they measure different things. 300 KB is file size, the number of bytes the image takes up. 300 DPI is print density, how many pixels are packed into each inch of paper. A 300 KB file can print sharply at 300 DPI if it has enough pixels for the print size you want. Divide the pixel width and height by 300 to get the largest sharp print in inches. A 2,400 × 1,800 image, for example, prints cleanly at 8 × 6 inches.
If a form asks for "300 DPI," it usually means the image must have enough pixels for a certain print size. Compressing to 300 KB won't lower the DPI unless it also reduces the dimensions, and you can prevent that with the "Dimensions" setting or by entering an exact size.
How the compression works
The tool first finds the largest dimensions that fit under your target at a high quality level, then searches for the best quality setting that still fits. Results typically land within 1 to 3 percent of the limit. The What matters most setting decides the tradeoff:
- Balanced keeps JPG quality at 70% or higher, which is very hard to tell from the original at normal viewing size. It resizes only if the image can't fit otherwise.
- Sharpness keeps quality at 85% or higher for close inspection, zoomable product photos, and prints.
- Dimensions keeps as many pixels as possible and lowers quality instead, for forms that check the width and height.
Tips for listing photos, portfolios, and documents
- Marketplace and real estate listings: buyers zoom in, so use "Sharpness" and leave the longest side unlimited. Clean backgrounds leave more of the budget for the item itself.
- Email and newsletters: a 1,600 to 2,000 px image at 300 KB looks crisp on any screen. Ten of them still fit comfortably under common attachment limits.
- Scanned documents: use black and white for text pages. Removing color keeps pages large enough to read fine print.
- Portfolios and contest entries: check the rules for a required pixel size. Enter it exactly and let the tool handle the file size.
Frequently asked questions
Is JPG compression to 300 KB lossless?
No. JPG always discards some detail, but at 300 KB the loss is usually invisible at normal viewing size, because the quality setting stays high. Use "Hold to compare" to check for yourself, zoomed in on the parts you care about.
Are my photos uploaded to a server?
No. Everything runs in your browser tab, and the page keeps working even if you disconnect from the internet after it loads.
Will the compressed photo still print well?
Each card shows the print size at 300 DPI. For a 4 × 6 print you need about 1,200 × 1,800 pixels, which almost any photo keeps at 300 KB. For larger prints, raise the target or use the original file.
My image is already under 300 KB. What happens?
A JPG that's already under the target is kept exactly as is, unless you've asked for a pixel size, a longest-side limit it exceeds, or black and white. Recompressing it would only lower the quality.
Does it strip EXIF data?
Yes. The compressed file is rebuilt from pixels, so GPS location, camera details, and other metadata are removed. Sideways photos are rotated upright first, so they display correctly everywhere.
Can I compress many photos at once?
Yes. Choose or drop as many as you like. They're compressed one after another with the same settings, and "Download all" saves them together in one ZIP file.
Why is my PNG screenshot larger after converting?
Screenshots and flat graphics with few colors are stored very efficiently as PNG and less efficiently as JPG. The card points this out when it happens. If the form accepts PNG, the original may be the better file to send.