MB to KB Converter: Compress Images to an Exact Size in KB
Use this MB to KB converter to shrink a photo to the KB limit on a form. 20, 50, 100, 200, or any number you type.
PNG transparency is filled with white, then saved as the format you pick.
Size, format, and KB counting
Your files never leave your device. Compression runs entirely inside your browser using your phone or computer's own processor. Nothing is uploaded to a server, nothing is stored, and the page keeps working even if you go offline after it loads. Re-encoding a photo builds a new file from pixels, so camera metadata such as GPS is removed. Read the privacy policy.
How to convert an image from MB to KB
- Choose a JPG, PNG, or WebP photo, or drop up to 20 photos on the box above. The page does not open your camera on its own.
- Type the KB number from the form, or tap 20, 50, 100, or 200. Strict mode caps the file at KB × 1000 bytes.
- Press Compress, check the byte count on the result card, then download. The new name looks like
photo-50kb.jpg.
A phone photo of about 3 MB is 3,000,000 bytes in the decimal count. A 50 KB strict target is 50,000 bytes, about 60 times smaller. The tool finds the highest JPEG quality that still lands at or under that ceiling. If even a low quality is too big, it reduces the pixel size and tries again. The short side never goes below 64 pixels. If that is still too big, it stops and tells you to raise the target.
The result card shows a before and after preview, the old size and the new size in bytes, the decimal KB and the binary KiB, and the new pixel size. A line says whether the file fits under the target. When more than one photo finishes, Download all (ZIP) packs them. On iPhone or iPad, long-press the preview if the download button does nothing.
Open the settings if you also need a minimum size, a maximum edge, or an exact width and height. Exact size can crop to fill the frame or fit the whole photo and add white edges. A locked ratio keeps the photo from stretching while you edit one side.
Which KB size should you choose?
Many online application systems print an upload limit next to the photo field. Read that note first, then pick a target a little under it. This page does not list exam boards, ministries, or portals, because those limits change and this site has not copied them from anywhere.
20 KB and under: signatures and thumbnail photos
A budget around 20 KB is common for a small headshot or a signature. Expect a softer picture. If the form also gives a pixel size, set that exact size so the bytes are spent on the crop you need, not on a huge original.
50 KB: passport-style photos on application portals
50 KB strict is 50,000 bytes. It is a frequent ceiling for a formal photo. Start here when the form says “under 50 KB” and does not ask for something smaller. If the face looks too soft, try 80 or 100 only when the form allows it.
100–200 KB: ID cards, certificates and clearer photos
100 KB to 200 KB keeps more detail for an ID scan or a certificate page saved as a picture. For a multi-page certificate, the PDF tool is a better fit than saving each page as a separate photo.
MB to KB conversion table
Decimal KB multiplies by 1000. Binary KiB multiplies by 1024. The same “MB” label can mean either system, which is why a phone and a form sometimes disagree. The full converter, including bytes and GB, is on the KB to MB page.
| MB label | Decimal KB (×1000) | Binary KiB (×1024) |
|---|---|---|
| 0.1 | 100 | 102.4 |
| 0.2 | 200 | 204.8 |
| 0.5 | 500 | 512 |
| 1 | 1,000 | 1,024 |
| 2 | 2,000 | 2,048 |
| 5 | 5,000 | 5,120 |
| 10 | 10,000 | 10,240 |
Why a form may still reject your photo
Size is only one check. A form can also refuse the file when the pixel size is wrong, when the format is not JPG, when the file name has spaces or symbols, or when the file is under a minimum size.
- Pixel size: set exact width and height, or move a signature to the signature resizer, which can work in centimetres and DPI.
- Format: JPG is the usual ask. PNG transparency becomes white here so the background does not turn black.
- File name: downloads use a simple name such as
photo-50kb.jpg. - Minimum size: turn on “Keep it above a minimum”. The tool raises quality and may enlarge up to twice the original. It does not pad the file with junk data.
If the upload is a scanned certificate rather than a single photo, compress the PDF instead of photographing the screen.
Your privacy
Your files never leave your device. Compression runs entirely inside your browser using your phone or computer's own processor. Nothing is uploaded to a server, nothing is stored, and the page keeps working even if you go offline after it loads. Re-encoding a photo builds a new file from pixels, so camera metadata such as GPS is removed. Read the privacy policy.
You can load this page, switch the device offline, and still compress. The photo is not posted to an analytics event. Events, when analytics is configured, record only a file type, a size range, a target, and a rough timing.
Frequently asked questions
How do I get a photo under 50 KB, 100 KB, or 200 KB?
Type 50, 100, or 200, or tap that preset, then press Compress. In strict mode those targets are 50,000, 100,000, and 200,000 bytes.
Is 1 MB 1000 KB or 1024 KB?
Both numbers are in use, and they describe different counting systems. In the decimal count, 1 MB is 1,000 KB (1,000,000 bytes). In the binary count, 1 MiB is 1,024 KiB (1,048,576 bytes), which is what some phones and Windows display.
This page defaults to strict mode: a 50 KB target means the file must be at or under 50 × 1000 = 50,000 bytes. A file that passes the stricter count also passes the 1024-byte count (51,200 bytes).
Open the size settings if a form tells you it counts 1024 bytes per KB. The result card always prints the raw byte count plus both KB readings, so you can compare them with the form.
Will my photo be uploaded anywhere?
No. Choosing a file only hands it to this page in your browser. Compression uses your phone or computer processor, then the download stays on your device.
You can prove it: load the page, turn off the network, and compress a photo. It still finishes. Re-encoding also drops camera metadata, including GPS, because the new file is built from pixels only.
Advertising or analytics scripts, when they are switched on, are not given the file name or the file bytes by this site. The processing code never posts the photo to a server.
Why does my compressed photo look blurry?
A very small KB budget cannot hold a large, sharp photo. Once quality is already low, the tool reduces the pixel size so the file can land under the limit.
That is why a 20 KB copy of a 12 megapixel picture looks softer than a 200 KB copy. Pick the largest KB the form allows, not the smallest number you have seen online.
If the form also asks for a pixel size, set exact width and height. The tool will fit the photo to that frame and then spend the byte budget on quality.
Can I make a photo bigger in KB?
Yes, when a form rejects files that are too small. Tick “Keep it above a minimum” and set the lower number, for example 10 KB under a 20 KB ceiling.
The tool raises JPEG quality first. If that is still under the minimum, it enlarges the photo up to twice the original edges. It stops there.
It will not stuff the file with useless bytes. If the highest quality is still under your minimum, the result says so instead of pretending the file grew.
Does it work on Android and iPhone?
Yes. Use the browser you already have. There is no app to install and no account to create.
JPG, PNG, and WebP are read directly. HEIC photos from some phones are read when the browser can decode them; otherwise the page loads a decoder only after a HEIC file fails to open.
On iPhone or iPad, if the download button does nothing, long-press the preview image and save it to Photos. The tool shows that hint on those devices.
Can I compress many photos at once?
Yes. Select or drop up to 20 photos. They are compressed one after another so a low-memory phone is less likely to crash.
Each photo gets its own download. When more than one photo finishes, Download all (ZIP) packs them into one archive.
A 21st photo is refused with a short message. Split the set and run it again. Nothing is uploaded either way.
What format do online forms usually accept?
Most photo fields ask for JPG or JPEG. PNG is less common, and many forms reject it or reject transparency.
This tool saves JPG by default and fills transparent pixels with white so a logo or scan does not turn black. WebP is available when you know the form accepts it.
Read the form’s own note for format, pixel size, and the maximum KB. Use a target a little under that maximum. The form’s instructions win over any preset on this page.