Check Image Size in KB
See exactly how big your image is (bytes, KB, pixels, type and DPI) and whether it meets your form’s limits.
What the checker reports
| Item | How it’s measured |
|---|---|
| Size | The exact number of bytes in the file, also shown in KB. A tick means it meets both your minimum and maximum. |
| Type | Read from the file’s own signature bytes, not from its name. |
| Pixels | Width × height as the image is displayed, after any camera rotation. |
| DPI | The density stored in a JPG’s header, if any. |
Bytes, KB and kB
1 KB is 1,024 bytes in the binary convention and 1,000 bytes in the decimal one (written kB). A 51,000-byte file is 49.8 KB in the first and 51.0 kB in the second, so it may pass one “50 KB” limit and fail another. The checker’s default “either” setting marks a file as passing only if it passes both readings.
Didn’t pass?
Press Resize to fit these limits and the same page makes a file that does. For more control, use the main 50 KB resizer, the 20–50 KB tool or the JPG converter.
Frequently asked questions
How can I check the size of an image in KB?
Choose the image above. The checker shows its exact size in bytes and KB, its width and height in pixels, its real file type and its DPI, and marks each against the limits you've selected. Nothing is changed until you press 'Resize to fit'.
Why does my phone show a different KB number?
Some apps count 1 KB as 1,000 bytes and others as 1,024, and some round. The byte count is the one number that never changes, so compare that with your form if it gives a limit in bytes, or check under both readings of KB.
What does 'real file type' mean?
The checker reads the first bytes of the file to see what format it actually is. A file named photo.jpg that is really a PNG inside is reported as PNG.
Where does the DPI value come from?
For JPG files, from the density field in the file header. Many photos don't set it, in which case the checker says so. DPI doesn't affect how many KB the file is.
Is the image uploaded to check it?
No. The file is read by your browser on your own device.