Visa portals, exam registrations, job sites and government forms rarely ask for a quality setting. They say "photo under 100 KB" or "signature between 10 and 50 KB" and reject anything bigger. This tool takes that number directly: you type the target in kilobytes and it works out the settings.
For each image it looks for the highest quality that still fits under your limit, and only if no quality is low enough does it make the picture smaller. The work runs inside your browser, so passport scans and ID photos never leave your device.
What compressing to a target size means
An ordinary compressor asks for a quality and tells you the size afterwards. A size-targeted compressor flips that around: the size is the fixed requirement and the quality is the unknown. Because JPG and WebP file sizes depend on how detailed a picture is, the same quality can give 60 KB for a plain passport photo and 400 KB for a busy street scene, so hitting a number means encoding, measuring and adjusting.
The tool counts 1 KB as 1,000 bytes. A target of 100 KB therefore means at most 100,000 bytes. Some upload checks count 1 KB as 1,024 bytes, which allows 102,400 bytes, so a file made here passes both kinds of check.
When a size limit decides for you
Application and exam forms
Online applications for passports, visas, university entrance exams and public sector jobs often set strict windows, for example a photo of 20 to 50 KB and a signature of 10 to 20 KB. Set the upper value as the target.
Profile pictures and marketplace listings
Some forums, older content systems and classified ad sites refuse images over 200 KB or 500 KB. Aiming just below the cap keeps as much detail as the site allows.
Email and helpdesk attachments
When a ticketing system or a mailbox caps each attachment at 1 or 2 MB, a target of 900 or 1900 KB gets a large phone photo through, usually at full width and height.
How the size search works
If the file is already in the output format and under the target, it is returned untouched, and its row says so. Otherwise it is decoded in a Web Worker and encoded repeatedly. First the tool tries quality 95 at full size. If that is too big, it tries quality 40, and when 40 fits it runs a binary search between 40 and 95 to find the highest quality that stays under the limit.
When even quality 40 is too heavy and Reduce dimensions if needed is on, the tool keeps quality at 40 and shrinks the width and height in proportion. It starts from an estimate based on how much too big the file was, then narrows down the largest scale that fits, and finally raises the quality again as far as that smaller size allows. The shorter side never goes below 16 pixels. With the option off, the dimensions stay as they are and the quality may drop as low as 5. If nothing fits, you get the smallest file the search produced and the row says the target was missed.
Come usare questo strumento
- Drop one or more JPG, PNG or WebP images on the box above. Each can be up to 50 MB.
- Type your limit in Target size (KB). It starts at 200 and accepts 5 to 50,000.
- Choose the Output format: Keep original, JPG or WebP, and leave Reduce dimensions if needed on unless the pixel size must not change.
- Press Convert. Each row shows the new size and whether it is under the target.
- Download the files one by one or use Download all (.zip).
Limitations
- PNG is lossless and has no quality to search, so a PNG is saved as JPG when you keep the original format. Transparent areas turn white in JPG; choose WebP if you need to keep them.
- Tiny targets for large photos force a big cut in width and height. If a form also demands exact pixel dimensions, resize first, then compress to size.
- Re-encoding drops EXIF data such as the camera model and GPS location. An image returned untouched because it was already small enough keeps its metadata.
- Each image is encoded several times, so large batches take longer than ordinary compression, especially on phones.