WebP is a modern image format created by Google that has quietly become the default choice for fast websites. If you have ever wondered whether to switch your images to .webp, here is what it does and when it makes sense.
We measured this ourselves. Across every source format we tested — PNG, JPG and BMP — WebP was the only target that never lost. PNG to WebP shrank all four test images, between 59% and 84%, and the transparent logo kept its transparency (28.8 KB down to 7.5 KB). No other output format managed that. see the full measurements
Why WebP exists
For years the web was split between two formats: JPG for photos and PNG for logos and transparency. WebP was designed to replace both. It supports:
- Lossy compression like JPG, but more efficient
- Lossless compression like PNG
- Transparency (an alpha channel)
- Animation, like GIF
In practice, WebP files are typically 25–35% smaller than an equivalent JPG at the same visual quality — that is the figure usually quoted, and it compares two lossy formats. Our own numbers below are much larger because they start from PNG, which is lossless: beating a format that stores every pixel exactly is a far easier contest than beating JPG. Both figures are right; they answer different questions.
The savings are not a rumour, so here is the measured version. Through our own PNG → WebP page: the photograph fell 1.88 MB → 303.1 KB (−84%), a UI screenshot 18.0 KB → 7.3 KB (−59%), a flat illustration 34.7 KB → 10.2 KB (−71%), and a transparent logo 28.8 KB → 7.5 KB (−74%) with its transparency intact. One format covering photographs and flat graphics and alpha is the whole reason WebP exists.
When to use WebP
Use WebP when:
- You control a website and want it to load faster — smaller images improve Core Web Vitals and SEO.
- You need transparency and small size at once, which JPG cannot give you.
- Your visitors use modern browsers (all current versions of Chrome, Edge, Firefox and Safari support WebP).
The most revealing measurement is one we did not go looking for. That same screenshot, converted from four different sources, lands in the same place every time: 7.3 KB from the 18.0 KB PNG, 7.3 KB from a 45.3 KB JPG, 7.3 KB from a 10.2 KB GIF, and 7.3 KB from a 2.75 MB BMP. The output size is decided by the pixels, not by the container they arrived in — which is why “convert everything to WebP” is a sane bulk policy in a way that most format advice is not.
When to stick with JPG or PNG
WebP is not always the answer:
- Sharing a file with someone who might open it in older software — JPG and PNG are universally supported.
- Uploading to a platform that rejects
.webp(some older tools and printers still do). - Print workflows, which typically expect JPG, PNG or TIFF.
When in doubt for compatibility, a plain JPG or PNG is the safe fallback.
Two measured exceptions keep this honest. A photograph already saved as JPG only fell 330.2 KB → 301.9 KB (−9%) — both are lossy and the JPEG was already efficient, so there is little left to win. And our 4.3 KB transparent GIF actually grew to 5.4 KB (+27%): against a tiny palette image a modern codec has nothing to reclaim. If the file is already small and already lossy, WebP is not free money.
How to convert to and from WebP
These free tools run entirely in your browser — nothing is uploaded:
- PNG to WebP — shrink logos and graphics while keeping transparency.
- JPG to WebP — make photos smaller for the web.
- WebP to PNG — get a widely compatible, lossless copy.
- WebP to JPG — for tools that only accept JPG.
The rule of thumb: use WebP on your own website for speed, and convert back to JPG or PNG whenever you need to hand a file to someone else.
How WebP compares to the formats it replaces
| JPG | PNG | GIF | WebP | |
|---|---|---|---|---|
| Photos | Good | Wasteful | Poor | Good |
| Transparency | No | Yes | 1-bit only | Yes (full alpha) |
| Animation | No | No | Yes (256 colours) | Yes (full colour) |
| Lossless option | No | Yes | Yes | Yes |
| Typical size | baseline | large | large | 25–35% smaller |
Against an animated GIF, a WebP version is often a fraction of the size with millions of colours instead of 256 — one reason GIF is slowly being retired.
What almost no comparison mentions is the cost of leaving. WebP is close to a one-way door: our 7.3 KB WebP screenshot became 82.3 KB as PNG (+1034%) and 45.5 KB as JPG (+527%); the 7.6 KB transparent logo became 36.9 KB as PNG (+388%). Only the photograph got cheaper going backwards, 351.5 KB → 281.2 KB as JPG (−20%), and it lost quality doing it. Keep the original of anything you may need to edit later.
Common misconceptions
- “WebP is only lossy.” It has both a lossy mode (derived from the VP8 video codec) and a fully lossless mode with transparency, so it can replace PNG as well as JPG.
- “WebP works in every app.” In browsers, yes. But many email clients, older photo viewers and some tools still stumble on
.webp, which is why keeping a JPG/PNG copy is handy. - “Bigger file means better quality.” WebP’s efficiency means a smaller
.webpcan look identical to a larger JPG. File size alone tells you little about quality.
And a misconception the numbers settle: WebP is not universally smaller. Coming from AVIF it always grew — our photo 122.3 KB → 234.4 KB (+92%) — and a 574-byte SVG rasterised to WebP came out 6.6 KB (+1082%). WebP beats JPG and PNG; it does not beat a newer codec, and it does not beat vector.
FAQ
Does WebP reduce image quality?
Lossy WebP discards some data like JPG, but usually less visibly at the same file size. Lossless WebP keeps every pixel exactly.
Why won’t my WebP open in an email or old program?
That software predates WebP support. Convert it to a JPG or PNG and it will open anywhere.
WebP or AVIF — which should I choose?
AVIF is usually smaller; WebP is faster to create and slightly more widely supported. See AVIF vs WebP vs JPEG for the full picture.