Compress any photo to an exact kilobyte target

Reduce image size in KB without sending the file away

Most “compress image to 100kb” tools upload the picture to a server, run a black-box encoder, and hand you a download. That is a poor fit for passport photos, Aadhaar-linked forms, and exam applications. ExactKB is a static website. The compressor is a canvas toBlob loop that binary-searches quality until the file is as large as possible while staying under your target. The bytes stay in this tab.

Start here for a custom target, or open a dedicated page if you already know the number:20 KB,50 KB,100 KB,200 KB, or500 KB. iPhone photos can go through HEIC to JPG; Chrome and WhatsApp downloads through WebP to JPG.

When you actually need an exact kilobyte

Generic “make it smaller” advice fails on government and job portals because the validator is a ceiling, not a vibe. If the field says 50 KB and your file is 61 KB, the form rejects you even if a human would call it compressed. Exact-KB queries exist because that rejection is binary and usually happens at 11 p.m. on a deadline.

Typical ceilings we see in the wild (always confirm the current PDF or help page):

• 20 KB — signatures, thumb impressions, a few photo fields. See compress to 20 KB.
• 50 KB — PAN photographs, many SSC / IBPS / RRB photo boxes, tight Passport Seva windows. See 50 KB.
• 100 KB — the default job-portal and UPSC-adjacent number, and the homepage target. See 100 KB.
• 200–240 KB — email attachments and many visa / DS-160 style uploads. See 200 KB.

If you are preparing a Civil Services photograph, start with the UPSC photo size guide. For travel documents, use passport photo compression. Neither guide replaces the official notice.

How the encoder decides quality vs pixels

JPEG and WebP sizes jump in steps. ExactKB cannot promise 102,400 bytes on the nose, and it will not pad junk bytes to fake a number. It promises the file is at or under the target and as high-quality as that budget allows. That is the rule forms actually enforce.

The loop tries high quality first. Each probe that still fits becomes the new best; each probe that misses lowers the ceiling. Only when the lowest usable quality is still too big does the tool shrink the longest side and try again. You can see that decision on the result card: original bytes, final bytes, pixels before and after, and the quality percentage. A longer walkthrough lives in how exact KB compression works.

By default a kilobyte is 1024 bytes — the figure Windows, macOS, and most phone file apps show. Some Indian portals still count 1000-byte kilobytes. Use the checkbox in the tool if you need the SI definition. When you are within a few hundred bytes of a hard cap, check the file in Explorer or Files after download; do not trust a screenshot of a progress bar.

Limitations — read these before you blame the tool

ExactKB changes file size, format, and optional max dimensions. It does not make a photograph “valid.” Composition, background color, head height, glasses, and smile rules are studio problems. We will not auto-crop a beach selfie into a 35 × 45 mm frame, replace a busy background, or certify a visa photo. If you need that, crop first in any editor, then compress here last.

• PNG output cannot quality-search. To hit a kilobyte target we reduce dimensions. Forms almost always want JPG.
• Transparent PNGs flatten onto white when you emit JPEG. That matches paper-form expectations.
• Canvas redraw always strips EXIF and GPS. There is no “keep metadata” path in this version.
• A few HEIC burst or Live Photo stills fail in-browser decode. Export a JPEG from Photos and drop that in.
• Very large panoramas are capped at 24 megapixels so a phone tab does not crash.
• We do not compress PDFs. That is a different product.

Tips that keep faces readable at 50–100 KB

You cannot store an 8 MB sensor dump in 100 KB and keep every pore. You can avoid the stupid losses. Light the face, crop before you encode, and do not screenshot a photo to “convert” it. Screenshots are the wrong codec and the wrong resolution. If 50 KB looks blocky, check whether the crop is 200 px wide — enlarge the crop, not a fantasy quality setting. More on this in compress without losing quality.

For signatures, photograph black ink on unlined white paper, crop tightly, and use 20 KB. Do not reuse the portrait JPEG. A full-color face forced to 20 KB will look like a stamp; that is physics, not a bug.

How to confirm the size after download

On Windows, right-click the file → Properties → Size. On macOS, Get Info. On Android, long-press in Files. On iPhone, the Files app shows the number ExactKB aimed at. If a portal still rejects you, the usual causes are: you uploaded the original, the field wanted JPG and you left PNG, the portal uses 1000-byte KB and you are 1–2 KB over in SI units, or the field also enforces pixels you did not set.

Privacy, ads, and what this site is not

There is no account and no watermark. Ads, when a publisher ID is added, sit below the tool and in article space — never as a fake download. ExactKB is not affiliated with UPSC, Passport Seva, USDS, banks, or universities named as examples. We do not promise advertising income and we do not review applications. Ownership and contact details are on the about and contact pages. The privacy policy explains that image bytes are not uploaded or stored.