Processed entirely on your device — nothing is uploaded
How to use the compress image to 300 kb
- 1Drop your image onto the box above — the 300 KB target is already selected.
- 2Leave the output format on the default (JPG) if this is for an upload portal.
- 3Wait a moment while the tool searches for the best quality under the cap.
- 4Check the reported size and dimensions, then download the 300 KB file.
What actually fits in 300 KB
The useful way to read 300 KB is as a pixel allowance. Mid-quality JPEG needs about 1.8 bits per pixel, which makes the allowance roughly 1,395,000 pixels — a 4:3 frame of around 1360 × 1020, or roughly 1,400 × 1,050 pixels — a full-width web image with detail to spare.
Prints well at postcard size. This is the first size on this list you could hand to a print shop without apology.
Those figures assume photographic content. Plain-background material — a signature, a form, a diagram — beats the 1360 × 1020 estimate handily at 300 KB, while dense textures like foliage or fabric undershoot it.
Where the 300 KB limit comes from
This page exists because upload forms reject files, and they reject them at round numbers. The situations that bring people here: an entrance-exam portal that allows up to 300 KB per image, a blog or CMS upload with a per-image budget, or a photograph emailed to a printer for a small print.
300 KB is generous by form standards: several national entrance portals set it as the ceiling for a photograph, which is many times what the photograph actually needs.
What makes a 300 KB rejection so irritating is the feedback loop — export, upload, get refused, guess again. A tool that takes 300 KB as an input and searches for the best encode under it removes the loop entirely.
How this tool reaches 300 KB exactly
The compressor binary-searches JPEG quality: encode, measure against 300 KB, halve the range, repeat. Eight rounds land within about one quality point of the largest encode that still fits, and since it all happens in this tab's memory, the search takes well under a second per image.
Most images fit under 300 KB on quality alone, but when one does not — the budget here is about 1,395,000 pixels — the tool scales dimensions down by the estimated factor and re-searches until it fits, reporting the final dimensions alongside the size.
On format: WebP reaches 300 KB at higher quality than JPG, and upload portals reject it anyway. Keep the default JPG output for anything with a size cap; save WebP for your own website.
It bears stating for a page that mostly handles signatures and identity photos: the entire 300 KB search runs locally in your browser. No upload happens at any point, so no copy of your document exists anywhere but your device.
Getting the best result at 300 KB
At 300 KB the workflow inverts: compress first, crop only if you want to. The 1,395,000-pixel budget swallows most photographs whole, so the tool's job is mostly undoing the extravagance of the camera's original export.
Batch the job: drop every photo for the email or listing at once. Each is compressed to 300 KB independently and the result list reports the saving per file, which makes the outliers — dense foliage, screenshots full of text — easy to spot and handle separately.
Keep the originals. 300 KB is a delivery size, not an archival one; the copy you upload or attach should never be the only copy that exists.
A ceiling this high is worth reading twice, because it is usually a ceiling and not a target. A 3.5 × 4.5 cm form photograph is fully served by 60–80 KB; uploading 300 KB of it changes nothing except how long the submit button spins on a bad connection during the last week of an application window. Use the headroom when the image is a document scan with small print — that is where the bytes actually buy legibility.
Frequently asked questions
How do I compress an image to exactly 300 KB?
Drop the image above — the target is preset to 300 KB on this page. The tool searches out the highest quality that fits under the cap, shrinking dimensions automatically if it must, and reports the final size before you download. No upload, no watermark, no sign-up.
Will my image still look good at 300 KB?
Almost always. At 300 KB most photographs show no loss you can see at normal viewing sizes — around 1360 × 1020 at healthy quality is comfortably within budget.
Why did the dimensions of my image change?
Because they had to. 300 KB is a budget of roughly 1,395,000 pixels of JPEG, and no quality setting squeezes a full-resolution photo under it. When quality alone cannot reach the target the tool rescales and searches again — the result line always reports the final dimensions.
Is my photo or signature uploaded anywhere?
No — there is no server in the loop. Everything from decode to the final 300 KB encode happens on your own device, which is the point when the image is a signature or an identity document.
The portal wants specific pixel dimensions as well as 300 KB. What order do I do that in?
Resize to the required dimensions first (the Image Resizer linked below does that), then compress the resized file to 300 KB here. In that order the compressor is not fighting excess pixels, so more of the budget goes to quality.
Does this work with PNG and WebP files too?
Yes — PNG, WebP and AVIF are all accepted and re-encoded toward 300 KB. PNGs convert to JPG by default, since lossless PNG cannot hit small byte targets on photographs, and JPG is what upload portals expect anyway.