Free JPEG Compressor Online

What the quality slider actually does to your JPG

JPEG works by splitting your image into 8×8 pixel squares and deciding how much detail each one keeps. At quality 95, almost everything stays and the file is large but looks perfect. As you lower the number, fine details start going first — fabric texture, background grain, subtle sky gradients. The image still looks fine on screen. It’s only when you get down around 30–50 that you start seeing blocky patches where the squares become visible.

File sizes you can expect at each quality range

Quality 90–100 — camera-grade

6–12MB for a 12MP photo. Needed for professional printing. Way too big for websites or email.

Quality 75–89 — web standard

800KB–2MB. Looks identical to the original on any screen. This is the right range for most websites.

Quality 55–74 — traffic-heavy sites

250–600KB. A slight loss of fine detail that you’d only notice zooming in. Common on news and e-commerce sites where speed matters.

Quality 30–54 — thumbnails

60–200KB. Visible noise on smooth areas like sky and skin. Only use for small previews.

Below 30 — extreme

Under 60KB. Looks rough on most images. Only makes sense for contact sheets or very low-bandwidth situations.

Compressing a batch of JPGs

Drop multiple files in at once and they all get compressed with the same quality setting. Keep in mind that two photos at the same quality setting can come out very different sizes — a photo full of detail compresses less than a simple landscape with mostly clear sky. Download them one by one or grab a ZIP when the whole batch is done.