# Compress Image to Exact KB — Compress an image to 20 KB, 50 KB or 100 KB on Mac

Hit a limit like 20 KB, 50 KB or 200 KB on the first try, or land inside a range like 20–50 KB. Part of OneMacTools, 151 private tools in one native Mac app (macOS 26 or later); category: Images. Runs on your Mac; nothing is uploaded.

Pick a target and OneMacTools searches for the highest quality that still fits, so you get the best-looking file under the limit instead of guessing. Set a minimum too, for forms that reject files that are too small. If a photo can't fit even at low quality, it can scale the picture down until it does.

Page: https://www.onemactools.com/tools/compress-image-to-kb · Download: https://www.onemactools.com/download · Pricing: https://www.onemactools.com/pricing

## How to use it
1. **Drop your photos.** One photo or a whole batch: each is compressed to the same limit.
2. **Choose the limit.** Pick 10 KB to 2 MB or type your own. Add a minimum if your form also rejects files that are too small, such as 20–50 KB.
3. **Choose the format.** JPEG for forms and portals, which almost always ask for it, or HEIC or AVIF for the smallest files.
4. **Click Compress.** Each file is saved at the best quality that fits, with the limit in its name, such as “50 KB”.
5. **Upload with confidence.** The files are saved in a new dated folder in Downloads › OneMacTools. Use the Preview (eye) button to check them or Show in Finder to find them for your upload.

## Options
- **Under:** The most each file may weigh: 10 KB, 20 KB, 50 KB (the default), 100 KB, 200 KB, 500 KB, 1 MB, 2 MB, or Custom.
- **Maximum (KB):** Shown for Custom: type the limit in KB, such as 75. You can also type a size in MB, such as 1.5 MB.
- **At least (KB, optional):** For forms that also reject files that are too small. Type 20 with a 50 KB limit and every file lands between 20 and 50 KB. It must be lower than the maximum.
- **Save as:** JPEG, HEIC or AVIF. Most upload forms and government portals only accept JPEG.
- **Make the picture smaller if it can't fit otherwise:** On by default. If a photo is still too big at the lowest quality, it's scaled down step by step until it fits. Turn it off to keep the pixel size; a photo that can't fit is then saved at the smallest size it can manage and you're told which ones missed.

## Tips
- Crop and resize first if the form asks for set pixels too. Use Resize Images, then compress here, so the quality goes into what's actually shown.
- Very small limits like 10 or 20 KB suit passport-style photos and signatures, not large landscape photos. Expect the picture to be scaled down to fit.
- Leave Save as on JPEG for official forms. HEIC and AVIF are often rejected even when they're under the limit.
- Use the minimum when a portal says something like 20–50 KB. Files that are too small get rejected just like files that are too big.
- For Indian exam portals with fixed pixels and a KB window, Exam Photo Resizer handles both in one step.

## Questions
**How do I reduce a photo to 50 KB or 20 KB?**
Choose the limit and click Compress. OneMacTools searches the quality setting in up to eight steps to find the highest one that still fits, so you get the best-looking file rather than an over-squashed one.

**What if the photo still can't fit?**
With “Make the picture smaller if it can't fit otherwise” on, it also scales the photo down until it does. If a target is impossible, you get the closest result and a note saying so.

**Why isn't PNG offered?**
PNG has no quality setting to tune, so it can't be aimed at an exact size. Use JPEG, HEIC or AVIF here, or Compress PNG for graphics.

**How do I get a photo between 20 and 50 KB?**
Choose 50 KB under Under and type 20 in At least. If a photo would come out under 20 KB even at full quality, it's enlarged slightly so it lands inside the window.

**How do I compress a photo to 100 KB or 200 KB for a form?**
Pick 100 KB or 200 KB, leave Save as on JPEG and click Compress. The file name shows the limit it meets, so you can find it quickly.

**Can I type a limit that isn't in the list?**
Yes. Choose Custom and type the number in KB, such as 75, or a size like 1.5 MB.