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Reduce Image Size to KB

Compress an image so it lands under a target size in kilobytes — a 20KB limit for a form, or 100KB for a website. Choose a file, set the target and this free reduce-image-size tool re-encodes it privately in your browser, then lets you download the result.

Choose an image

Target size (KB)

Output format

What does reduce image size to KB do?

Reducing an image to a specific size in KB means re-encoding a picture so its file size meets a target, such as 'under 20KB' or 'around 100KB'. Many forms, CMS platforms and websites enforce a maximum upload size, so you often need to shrink a photo or logo to qualify — without ruining its appearance.

The tool works by re-compressing the image, adjusting the quality and, when needed, scaling down the dimensions, until the file size fits the target. JPEG compression trades a little quality for a much smaller file; PNG is lossless but larger; WebP often gives the best balance. The goal is to hit the size you need while keeping the image as sharp as possible.

Everything runs in your browser, so your image is processed locally and never uploaded to a server.

How to use reduce image size to KB

Choose the image file you want to compress.
Enter the target size in KB (for example 20 or 100).
Pick the output format — JPEG, PNG or WebP.
Click Compress, then download the resized result.

Example

Your photo starts at 1.4 MB. Set a target of 20KB and choose JPEG; the tool re-encodes it under the limit while keeping it recognisable. Raise the target to 100KB and the same image comes out larger and sharper, and you can watch the before/after KB on screen.

Who is this image size reducer for?

Getting a picture under a size limit is one of the most common upload headaches, and a few groups hit it most often.

Job, visa and application seekers: forms often cap uploads at 20KB or 100KB, so a reducer gets a photo to fit under the limit.
Website owners and developers: smaller images mean faster page loads, lower bandwidth and better site scores.
Students: submitting assignments or scanned documents that must stay under a strict upload cap.
Photographers and sellers: preparing photos for social media or marketplaces that enforce a size ceiling.

Reduce image size chart — how scaling shrinks pixels

The tool re-encodes the image, adjusting quality and scale to fit the target. Because the final file size depends on the image content, this shows the deterministic dimension and pixel reduction for a 2000×1500 base image at the scale steps the tool tries.

Scale	Width	Height	Pixels	Area reduction
×1.00	2000	1500	3,000,000	0%
×0.75	1500	1125	1,687,500	44%
×0.50	1000	750	750,000	75%
×0.35	700	525	367,500	88%

Common use cases

Meeting a strict upload limit on a job application, visa or government form.
Squeezing images for a fast-loading website or an email attachment.
Preparing images for social media or marketplaces with size caps.
Shrinking a batch of photos before posting them to a gallery.

Pro tips

Set the target a little below the limit — re-uploads and headers add a few KB.
Use JPEG for photos and WebP for the web; reserve PNG for graphics with text or logos.
Pick the highest quality that still fits, rather than crushing the image for no reason.
Downscale very large dimensions first — reducing pixels saves far more size than lowering quality alone.

FAQ

How do I reduce an image to a specific size in KB?

Upload the image, set a target KB value and the tool adjusts quality and dimensions until the file fits under the target.

Is it private?

Yes. The image is processed entirely in your browser and never uploaded or stored on a server.

Why can't I hit a very small KB target?

Very small files need heavy compression and scaling, so the image may become blurry or lose detail. Lower targets eventually become impossible without severe quality loss.

Which format gives the smallest file?

WebP is usually the most compact for photos, JPEG is strong for photographic images, and PNG is best for graphics but larger for photos.

Does compression reduce quality?

Lossy compression like JPEG does reduce some quality, but at moderate settings the difference is rarely visible. PNG is lossless.

Can I choose the dimensions?

You can let the tool scale down automatically to hit the target, or rely on the size limit set.

Is there a file size limit?

The tool works in your browser, so it can handle images up to the memory available on your device.

What is a good KB for a website image?

Around 50–200KB is a reasonable target for most web images, depending on the page and the level of detail.