Format comparison

JPG vs WebP: is it worth switching?

Checked against the sources on 13 November 2026Sizes measured 13 November 2026

Short answer

For images on the web, WebP is usually the better choice: on this page's photo it was smaller than JPG at slightly higher fidelity, and on the graphic it was a fraction of the size and kept the transparent background JPG cannot store. JPG remains the right choice wherever compatibility outranks bytes: email attachments, upload forms that list only JPG, printing services and older software.

Two lossy formats doing the same job

Lossy WebP and JPG solve the same problem in the same broad way: predict and transform blocks of the image, then store the result with fine detail rounded away. The details differ. WebP's lossy mode is VP8 intra-frame coding, which predicts each macroblock's pixels from the already-reconstructed row above and column to the left and codes only what the prediction got wrong. Baseline JPEG transforms each 8 x 8 block's own samples and predicts only the block's average (DC) value from the previous block. On this page's photo, the newer design reached slightly higher fidelity in fewer bytes.

The difference is largest on images JPG handles badly. Flat colour and sharp edges cost JPG a lot, while WebP's coding copes better, and WebP can add an alpha plane so a cut-out keeps its transparent background. On the graphic sample that combination made the WebP a fraction of the JPG's size.

Where JPG still wins: everywhere outside the browser

Browsers are not the problem any more. MDN lists WebP support in current Chrome, Edge, Firefox, Opera and Safari, with the caveat that Safari on macOS needs Safari 14 on macOS Big Sur or later. The friction is elsewhere: upload forms that validate the extension and accept only .jpg (every exam notice summarised on AltFTool's exam-photo pages asks for JPG or JPEG), print services, older desktop editors, and recipients whose software you do not know.

In those places a WebP's smaller size is worth nothing if it is rejected. Keep JPG for anything that leaves your own site, and use WebP for pages you serve, ideally with a JPG fallback in a <picture> element if you care about very old browsers.

Converting existing JPGs

Re-encoding a JPG as WebP decodes the JPG's already-lossy pixels and compresses them again, so the WebP cannot be better than the JPG it came from and can be slightly worse. Convert from the original photo when you have it. When you only have the JPG, convert at a fairly high WebP quality and compare the two files at full size before replacing anything.

JPG or WebP, by destination

JPG or WebP, by destination
Destination	Choose	Reason
Your own web pages	WebP	Smaller at similar fidelity in this measurement, and broadly supported by browsers.
Email attachment	JPG	The recipient's software is unknown.
Exam or recruitment upload form	JPG	Every exam notice on AltFTool's exam-photo pages asks for JPG/JPEG files.
Product cut-out with transparency	WebP (or PNG)	JPG fills transparent areas with a colour.
Print service	What the service lists	Check its accepted types before converting; do not assume WebP is taken.
Archive of originals	Keep what the camera made	Each lossy re-encode can lose detail.

Measured example

JPG and WebP at quality 0.82 from the browser's canvas, same images
File	Bytes	Size	Fidelity to the original
Photo as JPG	86,531	84.5 KB	36.1 dB
Photo as WebP	71,574	69.9 KB	36.5 dB
Graphic as JPG (background filled white)	28,755	28.1 KB	39.0 dB
Graphic as WebP (transparency kept)	7,694	7.5 KB	38.3 dB

13 November 2026, Chromium 153.0.8010.12. Fidelity: PSNR against the original (higher is closer).

With the same quality number, 0.82, the photo's WebP was 69.9 KB against the JPG's 84.5 KB, 17% smaller, and its fidelity was 36.5 dB against 36.1 dB. The quality numbers of two different encoders do not mean the same thing, which is why the fidelity column matters more than the slider value.

The graphic shows the larger gap: 7.5 KB as WebP against 28.1 KB as JPG, with the WebP keeping its transparent background through an alpha chunk while the JPG had its background filled white.

How these files were made and measured

Questions

Is WebP smaller than JPG?

Usually, at similar quality. On this page's photo, WebP at the browser's quality 0.82 was smaller than JPG at 0.82 and slightly closer to the original. Results vary with the image and the encoder.

Should I convert all my JPGs to WebP?

For images on your own website, it is often worth it. For files you email, print or upload to forms, keep JPG. Convert from originals where possible, because re-encoding a JPG adds a second lossy step.

Why does a form reject my WebP?

Many upload forms accept only listed file types, often JPG and PNG. Convert the WebP to JPG with the WebP to PNG / JPG Converter and check the size limit.

Is WebP worth it for icons and graphics?

Yes, more than for photos. On this page's graphic sample WebP was a fraction of the JPG's size and kept the transparent background, which JPG cannot store.

Does the same quality number mean the same quality?

No. Each encoder maps its quality setting differently, so JPG at 0.82 and WebP at 0.82 are different targets. Compare the results, not the numbers.

Sources

Convert between them in your browser

Batch-convert JPG to WebP (or back) with a quality slider. The Image Converter runs in your browser tab, with no account.

Open the Image Converter