How to Convert Images to WebP on Mac (Free & Batch, 2026)

By Hieu Dinh

How to Convert Images to WebP on Mac (Free & Batch, 2026)

If your website feels slow, the culprit is almost always images. The fastest fix is to convert images to WebP on your Mac, because WebP files are typically 25-35% smaller than JPEG and PNG files at the same visual quality. Smaller files mean faster page loads, lower bandwidth bills, and better Core Web Vitals scores.

The good news: you do not need a subscription, a cloud account, or a slow upload to do it. macOS has everything you need to convert a single image or batch-convert an entire folder, completely offline. This guide walks through four methods, from a one-click drag-and-drop app to the cwebp command line, then gets honest about the situations where WebP is the wrong format.

What is WebP and why convert to it?

WebP is an image format developed by Google specifically for the web. It supports both lossy compression (like JPEG) and lossless compression (like PNG), and it handles transparency and animation in a single format. Before WebP, you needed PNG for transparent backgrounds and GIF for animation, with no single format that did both well.

The numbers are what matter. According to Google's own benchmarks, lossy WebP files are around 25-34% smaller than equivalent JPEGs, and lossless WebP files are roughly 26% smaller than PNGs, all at comparable visual quality. WebP is now supported in every major browser: Chrome, Firefox, Safari, Edge, and Opera.

If you want a deeper comparison against the newer AVIF format, see our breakdown of AVIF vs WebP.

Why convert images to WebP

There are three concrete payoffs when you convert images to WebP for a website:

  1. Faster page speed. Images are the heaviest assets on most pages. Shaving 30% off every image directly cuts load time, especially on mobile connections.
  2. Better SEO. Page speed is a Google ranking signal, and Core Web Vitals (specifically Largest Contentful Paint) reward fast-loading hero images. Smaller WebP files help you pass those thresholds.
  3. Lower bandwidth and storage costs. If you serve thousands of images from a CDN, a 30% reduction is a 30% cut in transfer costs.

The catch is that WebP is a delivery format, not necessarily your master format. We will cover that nuance later. For now, here are the four best ways to convert images to WebP on a Mac.

Method 1: Compresto (Mac, batch, offline)

Compresto is a native macOS app built for exactly this job: converting and compressing images in bulk without ever uploading them to a server. It is the method I reach for when I have more than one or two files, which is most of the time.

Compresto accepts JPEG, PNG, HEIC, and other common formats and outputs WebP directly. Because it runs natively on your Mac with hardware acceleration, it processes folders of hundreds of images in seconds rather than minutes, and nothing leaves your machine.

Here is how to convert images to WebP with Compresto:

  1. Download and open Compresto. The free trial lets you test it before buying.
  2. Drag a single image, a selection of files, or an entire folder onto the app window.
  3. Set the output format to WebP.
  4. Choose a quality level. Around 80 is a good default that keeps images crisp while cutting file size sharply.
  5. Decide whether to retain or strip metadata (EXIF, GPS, color profiles). Stripping it shrinks files further; retaining it preserves camera data.
  6. Click compress. Your WebP files are saved alongside the originals or to a folder you choose.

Because Compresto is fully offline, it is a strong fit if you handle client photos, medical imagery, or anything where uploading to a random web service is a privacy or compliance problem. It also doubles as a general-purpose compressor, so it overlaps with tools people search for as a TinyPNG alternative for Mac, an ImageMagick alternative for Mac, and a CloudConvert alternative for Mac.

Best for: batch jobs, privacy-sensitive files, and anyone who wants a one-click workflow instead of typing commands.

Method 2: The cwebp command line (best for one-offs)

If you live in the Terminal, Google's official cwebp encoder is fast, free, and scriptable. It is the engine behind many of the GUI tools and online converters, so you are using the same compression under the hood, just without the wrapper.

First, install it with Homebrew:

brew install webp

To convert a single image to WebP at quality 80:

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

The -q flag accepts a value from 0 to 100. The default is 75; 80 is a common sweet spot for photos. For graphics, logos, or screenshots where you need pixel-perfect quality, use lossless mode instead:

cwebp -lossless input.png -o output.webp

To convert every JPEG in the current folder in one go, loop over the files:

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

This is genuinely useful for quick, occasional conversions. The downsides: you have to remember the syntax, error handling is on you, and there is no preview, so you are guessing at quality until you open each file. For repeat batch work, a dedicated app like Compresto is less fiddly.

Best for: developers doing a quick one-off conversion or wiring WebP into a build script.

Method 3: Squoosh (web, single image)

Squoosh is a free, open-source web app from the Google Chrome team. It runs entirely in your browser, which means it processes images locally without uploading them, a meaningful privacy advantage over most online converters.

To use it:

  1. Open squoosh.app in any modern browser.
  2. Drag in a single image.
  3. Choose WebP from the format dropdown on the right.
  4. Drag the quality slider and watch the live before/after preview update in real time.
  5. Download the result.

The standout feature is the side-by-side slider that shows exactly what you are trading away as you lower quality. That makes Squoosh excellent for dialing in the right quality setting for a hero image you really care about.

The limitation is in the name of this section: it handles one image at a time. There is no folder or batch mode, so it is impractical for converting a product catalog or photo gallery.

Best for: carefully tuning a single important image with a visual preview.

Method 4: Online converters like CloudConvert (and the privacy trade-off)

Web-based converters such as CloudConvert, FreeConvert, and toWebP let you convert images to WebP without installing anything. You upload a file, the service converts it on their server, and you download the result. Some, like toWebP and AnyWebP, now process in-browser without true uploads, but many still send your files to a remote server.

The workflow is simple:

  1. Open the converter in your browser.
  2. Upload your image or images (free tiers usually cap the count and file size).
  3. Select WebP as the output format.
  4. Download the converted files, sometimes one by one, sometimes as a zip.

The convenience is real, but so are the trade-offs. You are sending your images to a third-party server, which is a non-starter for confidential or client work. Free tiers throttle batch size and resolution, and large uploads are slow on a typical home connection. If you find yourself bumping into those limits, an offline Mac app removes all of them at once. We cover that comparison in detail in our CloudConvert alternative for Mac guide.

Best for: a one-time conversion of a non-sensitive image when you cannot install anything.

When NOT to use WebP

WebP is excellent for the web, but it is not a universal replacement for JPEG and PNG. Here is an honest list of when to skip it:

  • Print and design handoff. Print shops, design tools, and many client workflows expect TIFF, PNG, or high-quality JPEG. WebP support in professional print pipelines is still spotty.
  • Older or specialized software. Some legacy content management systems, older versions of Photoshop, and various internal tools still cannot open WebP. If your destination cannot read it, the smaller file is useless.
  • Your master/archive copy. WebP, used lossily, is a delivery format. Keep your original JPEG, PNG, or RAW file as the archival master and generate WebP copies for the web. Never delete your only high-quality original in favor of a compressed WebP. The standard practice is JPEG (or RAW) as the archive and WebP as the delivery format.
  • Email and document embedding. Email clients and word processors have inconsistent WebP support. Stick with JPEG or PNG when embedding images in documents you will send to others.

If you ever need to go the other direction, you can convert WebP back to JPG just as easily. And if you are still deciding which format to standardize on, our guide to the best image format for websites lays out the full decision tree.

Batch converting hundreds of images

This is where the method you pick really matters. Converting one logo is trivial in any tool. Converting a 500-image product catalog separates the workflows that scale from the ones that do not.

Online converters fall down here first: free tiers cap you at 10-20 files, and uploading hundreds of full-resolution photos over a home connection is painfully slow. Squoosh is single-image only. The cwebp loop works but offers no progress feedback, no preview, and no easy way to also resize while you convert.

A native batch app is the practical answer for volume. With Compresto, the batch flow is identical to converting one file, you just drop the whole folder instead:

  1. Select an entire folder of images in Finder.
  2. Drag it onto Compresto.
  3. Set WebP as the output and pick your quality once.
  4. Optionally resize to a max width so oversized photos shrink further.
  5. Run it. Hardware acceleration handles hundreds of files in seconds, fully offline.

Because there are no upload limits and no per-file clicking, batch conversion stops being a chore. If your end goal is web performance rather than just format conversion, pair this with the tactics in our image optimization for web guide, and if you are converting graphics specifically, see the dedicated PNG to WebP converter walkthrough.

Frequently asked questions

Does converting to WebP reduce image quality? Lossy WebP discards some data, like JPEG, but at quality 80 the difference is invisible to the eye while files shrink 25-35%. For graphics and screenshots, use lossless WebP to preserve every pixel with no quality loss at all.

Can I convert images to WebP on Mac without installing anything? Yes. Squoosh and browser-based converters run in Safari or Chrome with no install. But for batch jobs or private files, a native app like Compresto is faster and keeps everything offline.

Is WebP supported on all browsers and devices? Effectively yes. Every current major browser, including Safari on macOS 11 and later, iOS, Android, Chrome, Firefox, and Edge, displays WebP. The remaining gaps are in older desktop software and print tools, not browsers.

What quality setting should I use when I convert images to WebP? Quality 80 is the standard sweet spot for photos, balancing sharpness against file size. Drop to 70-75 for thumbnails where size matters more, and use lossless mode for logos, icons, and text-heavy graphics.

Should I keep my original JPEG or PNG files after converting? Yes, always. Treat WebP as a delivery format and keep your originals as the master archive. If a client or print shop later needs a high-quality file, you will have it, and you can re-export to any format you need.

The bottom line

For a single image you want to fine-tune, Squoosh and its live preview are hard to beat. For a quick developer one-off, the cwebp command line is fast and free. Online converters work in a pinch when you cannot install software and the files are not sensitive.

But for the common real-world case, converting a folder of photos or product images, privately and at speed, a native Mac app wins. Compresto converts and compresses JPEG, PNG, and HEIC to WebP in true batch, with hardware acceleration, metadata control, and zero uploads. It is a one-time purchase with a free trial, so you can convert your first folder before deciding.

Try Compresto free and convert your images to WebP in seconds.

Ready to compress your files? Join thousands of creators using Compresto ⚡