Compress an image to 40 KB
Reduce a photo or signature to under 40KB for an exam, visa or job application. Exact size, JPG output, free, and nothing is uploaded.
Last updated
40 KB is a common limit for the photo on an application form: exam registrations, visa and passport services, job and scholarship portals. A head-and-shoulders photo fits it comfortably at the size forms display it. A full-size phone photo does not, so it is made smaller as well as compressed, and this page does both until the result fits.
What fits in 40 KB
A photograph up to about 432 × 288 pixels at high quality, or 591 × 394 at the lower quality most forms accept. That is measured on a detailed outdoor photo; a portrait against a plain wall fits larger.
A signature on white paper up to about 1520 × 570 pixels, more than any form asks for.
Is 40 KB enough?
A photo on an application form, shown at about 200 × 230 pixels: yes, at high quality.
A profile picture at 400 × 400: yes, at the lower quality forms accept.
A passport photo printed at 35 × 45 mm (413 × 531 pixels at 300 dpi): yes, at the lower quality forms accept.
A photo shown across a phone screen, about 1080 × 720: not at full size; at 40 KB it comes out smaller.
A photo filling a Full HD screen, 1920 × 1080: not at full size; at 40 KB it comes out smaller.
40 KB against the sizes either side
The same photograph reaches about 432 pixels wide at 40 KB, against about 368 pixels wide at 30 KB and about 485 pixels wide at 50 KB. If the form allows more than 40 KB, the next size up is a visibly sharper picture.
When the form also gives pixel dimensions
Forms often say something like "under 50 KB, 200 × 230 pixels". Resize to the dimensions first with Resize Image: a picture already at the right size needs very little compression to fit, and comes out much sharper than one squeezed down from full size.
If the website still says the file is too big
This page counts 40 KB as 40,960 bytes. Some sites count it as 40,000, which is a little less. If yours is strict, aim for the next size down.
Questions
How do I compress an image to 40KB?
Add it to this page and press the button. The JPG quality is lowered step by step and, if that is not enough, the pixel size, and the best version under 40 KB is kept. For a typical photo that ends up about 432 pixels wide.
How many pixels is a 40KB photo?
About 432 × 288 at high quality, or 591 × 394 at a lower one, for a detailed photograph. A simpler picture fits more pixels in the same size.
Can I compress a PNG or an iPhone photo to 40KB?
Yes. PNG, HEIC and WEBP are all read and saved as JPG. To fit 40 KB, a detailed photo comes down to about 591 pixels wide at the quality forms accept; a scanned signature keeps up to 1520.
Is my photo uploaded?
No. It is compressed in your browser, on your own device.