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Compress image to KB

Pick a target — 10 KB, 20 KB, 50 KB, 100 KB, 1 MB or your own — and every photo is compressed to land just under it, never over. Ideal for exam, job and visa forms. Compress many images at once and download them as a ZIP; nothing is uploaded.

  • Free
  • No sign-up
  • Private — runs in your browser

How to compress an image to 20 KB, 50 KB or 100 KB

  1. 1Pick a target size: 20 KB, 50 KB, 100 KB… or type your own.
  2. 2Add one or more images (JPG, PNG, WebP, and HEIC where your browser supports it).
  3. 3Each image is compressed just under the target. Slide the before / after view to check the quality.
  4. 4Download each image, or all of them as one ZIP file.

How compressing to an exact KB size works

  1. 01Find the highest JPG/WebP quality whose file ≤ target (binary search, about 8 tries)
  2. 02If even quality 5 % is too big: pixels × √(target ÷ size), then search again
  3. 031 KB = 1,000 bytes here, so the file also passes forms that count 1 KB as 1,024 bytes
  4. 04Saved % = (original size − new size) ÷ original size × 100

JPG and WebP are "lossy" formats: a quality setting decides how much fine detail is thrown away, and the file gets smaller as quality drops. The size can't be predicted exactly, so the tool searches for it: it tries a quality in the middle, then halves the gap up or down depending on whether the file was too big, about eight times. The best result under your target is kept — never one over it.

Some targets are too small for a full-size phone photo even at the lowest quality. File size grows roughly with the number of pixels, so the tool then reduces the width and height by the square root of the overshoot and searches again. A 12-megapixel photo usually needs fewer pixels to fit 20 KB; a passport-size photo of about 400 × 500 px fits easily and stays sharp.

PNG is lossless — it keeps every pixel exactly, so it has no quality setting and its size depends only on what is in the picture. That is why PNG can't be compressed to a chosen KB size and images are saved as JPG or WebP instead.

Good to know

  • Exam forms (SSC, IBPS, NEET and others) often limit pixels as well as KB — resize to the right pixel size first, then compress.
  • Crop photos of documents and signatures tightly before compressing: less background means more detail in the same KB.
  • Use JPG when a form says "JPG/JPEG only"; WebP is smaller but not accepted everywhere.
  • If a 20 KB photo looks blurry, try 30–50 KB if the form allows it — the difference in sharpness is large.

Compress image to KB — common questions

How do I compress a photo to 20 KB?

Tap 20 KB, keep JPG and add your photo. It is compressed to just under 20 KB. A large phone photo is also reduced in pixels so it can fit; you'll see the final size in pixels and KB before you download.

Will the file ever be over my limit?

No. Only a result at or under the target is kept. 1 KB is counted as 1,000 bytes, so a "50 KB" file is at most 50,000 bytes and also passes forms that count 1 KB as 1,024 bytes.

Why did my image get smaller in pixels?

When even the lowest JPG quality is above the target, there are too many pixels for that size. The width and height are then reduced step by step until the file fits, keeping the shape the same.

Why can't I choose PNG?

PNG is lossless, so it has no quality setting to lower — its size depends only on the picture. To hit a KB target the image must be saved as JPG or WebP.

Is it safe for ID cards and documents?

Yes. Everything happens in your browser; the images are never uploaded or stored on a server.

How many images can I compress at once?

As many as your device's memory allows — dozens are fine. They are compressed one after another, and you can download them one by one or together as a ZIP.

Sources

Formulas last reviewed: September 30, 2026 ·How we check our formulas

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