How to Batch Convert PNG and JPG to WebP on a Mac (3 Ways Compared)

Published by @SoNiceInfo at 9/21/2026


The easiest way to batch convert PNG and JPG images to WebP on a Mac is to drag and drop them into a GUI app such as WebP Converter.: you can check the quality with your own eyes before exporting, and your images stay on your Mac. If you're comfortable in the terminal, the cwebp command installed via Homebrew also works offline and handles hundreds of files in one go. For a handful of non-sensitive images, an online converter is a third option.

Note that the sips command built into macOS cannot write WebP, so the built-in tools alone won't get you there (details below).

The three methods compared

ItemGUI app (WebP Converter.)cwebp (command line)Online converter
Batch conversion✅ Drag and drop whole folders✅ With a shell loop△ Limits on file count and size
Offline / privacy✅ Stays on your Mac✅ Stays on your Mac❌ Uploaded to a third-party server
GUI✅❌ Terminal✅ Browser
SetupInstall from the Mac App StoreHomebrew and the webp packageNone
Before/after comparison✅ Comparison slider❌ Open the files yourself△ Depends on the service

RecommendedMethod 1: Batch convert with a GUI app (WebP Converter.)

A GUI app is the better fit if you'd rather avoid the terminal, or if you want to check the converted quality with your own eyes as you go. With WebP Converter., a batch WebP converter app for Mac, conversion takes three steps:

1

Drag and drop your images

Drop PNG, JPG, HEIC, or GIF images — or a whole folder — onto the window.

2

Choose the quality

Pick lossy (quality 80, for example) or lossless, and set resizing or a watermark if you need them.

3

Hit Start

Conversion starts, and everything you dropped in is converted to WebP in one batch.

A before/after comparison slider lets you see how far you can lower the quality before exporting anything. It can also convert animated GIFs to animated WebP. All conversion happens on your Mac and your images are never sent off the machine. It's free to start.

If you need to export to several formats at once — AVIF or JPEG XL as well as WebP — take a look at Image Tool+, an all-in-one image processing app.

See WebP Converter. →

macOS 12+ · Apple Silicon native

For terminal usersMethod 2: Convert with the cwebp command

If you live in the terminal, cwebp — Google's official WebP encoder — is a great choice. It's also easy to wire into build scripts and CI. Install it with Homebrew:

brew install webp

To convert a single file, pass the quality (-q, 0–100) and the output path (-o):

cwebp -q 80 input.png -o output.webp

For logos, screenshots, and anything you don't want degraded, use lossless:

cwebp -lossless input.png -o output.webp

To convert every PNG and JPG in a folder, use a shell loop. The originals are kept, and a file with the same name and a .webp extension is created next to each one.

for f in *.png *.jpg; do cwebp -q 80 "$f" -o "${f%.*}.webp"; done

In zsh, the default shell on macOS, you'll get a "no matches found" error if the folder contains no files with one of those extensions. In that case, list only the extensions you actually have (for example for f in *.jpg; do ...). Also note that cwebp cannot read HEIC directly, so iPhone photos need to be converted to JPEG or PNG first.

Measured: how much smaller?

Here is what I got with a single image on my Mac (cwebp 1.6.0). It's just one example — savings vary with the content of the image.

Source (1600×1064)CommandResultSavings
JPEG, 230 KBcwebp -q 80112 KBAbout 51% smaller
PNG, 1.86 MBcwebp -lossless1.24 MBAbout 33% smaller

A few non-sensitive imagesMethod 3: Use an online converter

Services that convert images you upload through the browser need no installation and are handy for a few files. Keep in mind, though, that your images are uploaded to a third-party server. Photos can carry EXIF data such as the capture time and location, so this isn't a good fit for unreleased product shots, client assets, or internal documents. Free tiers also tend to limit the number of files and the file size per batch, which makes them impractical for converting hundreds of images.

Can't the built-in macOS tools do it?

You might expect the built-in command-line tools to handle this, but the built-in sips command can't write WebP. macOS has been able to display WebP since macOS 11 Big Sur, so Finder and Preview open WebP files fine. However, at the time of writing (macOS 27), the built-in image conversion command sips does not support writing WebP. You can list the supported formats with this command:

sips --formats | grep -i webp

The JPEG, PNG, and HEIC lines are marked "Writable", but the WebP line is not. When I actually ran sips -s format webp, no file was produced. So to convert to WebP, use one of the three methods above.

Which method fits you

  • Photographers — the GUI app. You can judge the compressed quality by eye with the slider, and photos carrying EXIF capture time and location are processed entirely on your Mac.
  • Web creators and bloggers — the GUI app for converting a batch per article or project; cwebp if you want conversion inside a build script.
  • Engineers — cwebp. It drops easily into shell loops and CI, with fine-grained options.

Which quality setting to use

  • Photos and images with gradients — lossy, quality 75–85. Start at 80 and lower it gradually while it still looks fine.
  • Logos, screenshots, line art — lossless. Edges stay crisp, and images with large flat areas often end up smaller too.
  • Transparent PNGs — WebP keeps the alpha channel even in lossy mode.

Add a fallback with the picture element

WebP is supported by all current major browsers, but if you care about older clients you can keep the original JPEG/PNG as a fallback with <picture>:

<picture>
  <source type="image/webp" srcset="/images/photo.webp" />
  <img src="/images/photo.jpg" alt="Description of the photo" />
</picture>

For even smaller files, you can put AVIF first in that list. See how to convert images to AVIF on a Mac, and WebP vs AVIF for when to use which.

FAQ

Q. Can I convert images to WebP with only the tools built into macOS?

Not at the time of writing (macOS 27). The built-in sips command can read WebP but cannot write it. You can check this by running sips --formats | grep -i webp: the WebP line has no "Writable" flag. To convert to WebP you need to add an app or a tool such as cwebp.

Q. What WebP quality setting should I use?

For photos and images with lots of gradients, lossy quality 75–85 is a good range. For logos, screenshots, and line art with large flat areas of color, lossless keeps edges crisp and can even produce a smaller file.

Q. How much smaller does WebP make an image?

In one example on my Mac, a 1600×1064 JPEG of 230 KB became 112 KB with cwebp -q 80 (about 51% smaller). The same image as a 1.86 MB PNG became 1.24 MB with lossless WebP (about 33% smaller). Results vary with the content of the image.

Q. Can I convert HEIC photos from an iPhone to WebP?

cwebp cannot read HEIC directly, so you have to convert to JPEG or PNG first. WebP Converter. accepts HEIC as input, so you can drag and drop iPhone photos and convert them to WebP as they are.

Q. Is it safe to use an online converter?

With an online converter, your images are uploaded to a third-party server. Photos can carry EXIF data such as the capture time and location, so for unreleased assets, client work, or internal documents it is safer to use a method that runs entirely on your Mac.

Summary

To batch convert PNG and JPG to WebP on a Mac, start with WebP Converter., which lets you work in a GUI and check the quality as you go. If you're comfortable in the terminal, cwebp does the same job. Both run entirely on your Mac, with no uploads.



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