How to Compress JPEG File Size (Quality Settings, 50 KB, 150 KB)
Reduce JPEG file size the right way: what quality setting to use, how to hit 50 KB or 150 KB, and whether JPEG and JPG are different.
To compress a JPEG file, save it again at a lower quality setting, and if it needs to be much smaller, reduce its pixel size too. Open compress JPEG, choose the photo, and either pick a quality (70–80% is the sweet spot) or type an exact size such as 50 KB or 150 KB. The new file usually looks the same as the original and is many times smaller. Everything happens in your browser, so the photo is not uploaded.
That covers most cases. The rest of this guide explains what the quality setting really does, so you can make good choices when a form or a website has a strict limit.
How to compress JPEG file size, step by step
- Open compress JPEG.
- Choose one or more JPEG files (or drop them on the box).
- Pick how to compress:
- Quality: drag the slider. 70% is the default.
- Target size: type a limit in KB or MB.
- Check the before and after size and the percentage saved.
- Download each file, or all of them as a ZIP.
Files are saved with -compressed added to the name, so the original stays safe.
What the JPEG quality setting actually does
JPEG splits the picture into small blocks and stores each block as a mix of smooth patterns. The quality setting decides how precisely those patterns are stored. At high quality almost everything is kept. At lower quality the fine detail, mostly tiny colour variations your eyes are not sensitive to, is rounded off.
The useful thing to know is that the relationship is not even. Dropping from 100% to 85% often halves the file with no visible change. Dropping from 85% to 70% saves a lot more with very little change. Below about 50%, savings slow down and damage speeds up: you start to see blocky squares in skies and halos around edges.
| Quality | Typical look | Use it for |
|---|---|---|
| 90–95% | Same as original | Master copies, printing |
| 75–85% | Same as original on screen | Sharing, websites, email |
| 60–70% | Very slight softness when zoomed | Thumbnails, quick uploads |
| 40–50% | Visible artefacts on close look | Only when size is critical |
| Below 40% | Blocky | Resize the image instead |
These are typical results. Photos with a lot of fine detail show artefacts sooner than simple ones.
Compress JPEG to 50 KB
50 KB is a common limit for exam and job form photos. Use compress image to 50 KB, which is the same tool with the target already set.
It works best when the photo is already small in pixels. A passport-style photo at a few hundred pixels fits in 50 KB at high quality. A full phone photo does not, so the tool shrinks it to a size that does fit, rather than turning it to mush, and notes the new dimensions.
For exam photos, crop and resize to the size in your notice first. If the form also has a minimum, such as 20–50 KB, use the exam photo resizer, which stays inside the range. The 20 KB and 50 KB guide covers exam photos in detail.
Compress JPEG to 150 KB (and other numbers)
For any limit, open compress JPEG, set Compress by to Target size, and type the number, for example 150. The tool searches for the highest quality that fits and tells you if it had to reduce the dimensions.
Common targets and the matching presets:
- 50 KB: compress image to 50 KB
- 100 KB: compress image to 100 KB
- 150 KB: type 150 in Target size
- 200 KB: compress image to 200 KB
If the form says "less than 150 KB", aim a little lower, such as 145 KB, because portals do not all count kilobytes the same way.
JPEG vs JPG: is there a difference?
No. JPEG and JPG are two names for the same format, from the Joint Photographic Experts Group. The shorter .jpg extension became common because early versions of Windows only allowed three-letter extensions. A file called photo.jpeg and one called photo.jpg are the same kind of file. If a form says "JPG only", a .jpeg file is fine, and renaming the extension between the two changes nothing inside.
What is different is JPEG vs PNG, WebP or HEIC. Those are genuinely different formats, and a portal that wants JPG will reject them. Convert with PNG to JPG, WebP to JPG or HEIC to JPG.
Resize or compress? Usually both
Compression changes how much detail is stored per pixel. Resizing changes how many pixels there are. For a big reduction, doing both gives the best result:
- Resize to the size the image will actually be seen at, with resize image. A website image rarely needs more than 1600–2000 pixels wide; a form photo needs a few hundred.
- Compress at 70–85% quality, or to the KB target.
A 1200-pixel JPEG at 80% quality looks better than a 4000-pixel one at 30%, and it can be the same file size.
Does compressing a JPEG again make it worse?
Yes, a little each time. Every save at a lossy quality rounds the data again. One or two saves at 80% are fine; ten saves will show. Keep the original, and always compress from it rather than from an already-compressed copy.
The tool helps here: in Target size mode, if your JPEG is already under the limit, it keeps the original as it is instead of re-saving it.
Common mistakes
- Using 100% quality "to be safe". It makes the file much bigger for no visible gain. 90% is plenty even for printing.
- Going very low on quality for a large photo. Resize instead.
- Renaming .png to .jpg. That only changes the name, not the format. Convert it properly.
- Forgetting the minimum size on forms. Read the full upload rule.
JPEG compression is a balance between file size and detail, and for almost every everyday use, 70–85% quality at a sensible pixel size is the right answer.
Questions
What JPEG quality setting should I use?
For photos, 70–85% looks the same as the original to most people and is much smaller. Use 50–60% for thumbnails or when the file must be very small, and avoid going below 40% unless you also reduce the pixel size.
How do I compress a JPEG to 50 KB?
Open compress image to 50 KB, choose the JPEG and download. It finds the highest quality that fits under 50 KB and shrinks the dimensions slightly only if the quality would otherwise drop too far.
Is JPEG the same as JPG?
Yes. They are the same format. Old versions of Windows limited file extensions to three letters, so .jpg became common, but .jpg and .jpeg files are identical and any form that accepts one accepts the other.
How do I compress a JPEG to 150 KB?
On compress JPEG, set Compress by to Target size and type 150 in the Max file size box. The result will be just under 150 KB.
Can I compress many JPEG files at once?
Yes. Select them all in compress JPEG. Each is compressed with the same settings, and you can download them together as a ZIP.