SVG is an XML description of shapes, which is why it scales to any size. WebP is lossy or lossless depending on the encoder, with alpha and animation. ImageMagick sits between the two, and this page says exactly what happens to an SVG file on the way to becoming a WEBP one.
What runs when an SVG file becomes WEBP
ImageMagick 6.9.12, on a machine we rent and watch. Your SVG file is uploaded once, ImageMagick runs once, the WEBP comes back, and neither file is kept. SVG to WEBP is one of the 3649 pairs that engine was probed on with a real file, which is why it has a page here and why the pairs the probe could not prove do not.
What survives from the SVG into the WEBP
The pixel dimensions of your SVG file. The WEBP comes out the size the SVG went in, because nothing on this path resizes anything.
Transparency. SVG and WEBP both carry a real alpha channel, so a cut-out sent as SVG is still a cut-out as WEBP.
What SVG to WEBP costs you
Scalability. SVG describes shapes, WEBP stores a grid of pixels, and the engine rasterises at 150 dots per inch on the way across. That density is a deliberate choice: at the 72 dpi ImageMagick defaults to, an A4 SVG page comes out 595 pixels wide and reads as a failed conversion. Enlarge the WEBP afterwards and it blurs, because there is nothing left to redraw from.
If a model is going to read the WEBP
A WEBP file is pixels, and pixels are expensive for a model to read. Handed this WEBP, an assistant spends its budget looking at the picture rather than reading it, and it will paraphrase what it thinks it saw. If your SVG is mostly words, the useful move is to pull the text out of it, not to change which picture format holds it.
SVG to WEBP, measured rather than promised
Running SVG to WEBP against the real engine with a real file, ImageMagick wrote 608 bytes of WEBP in under a tenth of a second, machine otherwise idle. That is one SVG file on one day and not an average, which is why the number is given together with the file that produced it.
The SVG to WEBP verdict was reached by a format signature, meaning at least four bytes unique to the format were found at the right offset. Which check was used matters, because they do not all prove the same thing, and a status code of 200 proves nothing whatsoever about whether the WEBP file has anything inside it.
The same SVG file, sent somewhere else
Other outputs the probe measured out of an SVG file, so the cost of choosing WEBP can be read against something. Sizes do not compare across engines, because each family was probed with its own SVG witness file.
SVG to PDF: 4,195 bytes in under a tenth of a second, verified by a format signature.
SVG to JPG: 2,483 bytes in under a tenth of a second, verified by a format signature.
SVG to PNG: 1,268 bytes in under a tenth of a second, verified by a format signature.
SVG to GIF: 1,232 bytes in 0.1 seconds, verified by a format signature.
SVG to TIFF: 2,464 bytes in under a tenth of a second, verified by a format signature.
Other ways into WEBP, and what they measured
Among the published routes into WEBP, SVG is the second largest output of the 8 measured. The witness files differ, so this ranks the probe run and not your document.
TIFF to WEBP: 370 bytes in under a tenth of a second.
PNG to WEBP: 370 bytes in under a tenth of a second.
JPG to WEBP: 350 bytes in under a tenth of a second.
PDF to WEBP: 906 bytes in 0.1 seconds.
HEIC to WEBP: 416 bytes in under a tenth of a second.
What we will not pretend about SVG to WEBP
An SVG file over 25 MB is refused before the upload finishes rather than after it, so you do not wait for a rejection.
An SVG to WEBP run that passes 30 seconds is killed, and the ImageMagick process is killed with it. A run left behind would sit on one of the machine's two cores until somebody noticed.
No text is read out of the SVG anywhere on this path. Converting a picture to WEBP never turns it into words, whatever the picture happens to contain.
ImageMagick was not saturated at sixteen simultaneous conversions: it held 47.5 a second while latency moved from 0.22 s to 0.34 s, and the service memory did not move off 51 MB. That is the measured headroom behind SVG to WEBP, not a marketing number.
One SVG file at a time, chosen in the browser. There is nothing else to set up and nothing else on offer.
SVG to WEBP: what people ask
What actually converts my SVG file to WEBP?
ImageMagick does it, 6.9.12, on a machine we rent and watch. Not a browser trick and not somebody else service: the SVG file is uploaded once, ImageMagick runs once, the WEBP comes back, and neither file is kept afterwards.
How long does SVG to WEBP take?
On the file the probe used, ImageMagick took under a tenth of a second and wrote 608 bytes of WEBP. That is one real measurement on one real SVG file, not an average and not a promise about yours: a larger SVG takes longer, and past 30 seconds the run is stopped.
What do I lose going from SVG to WEBP?
The one to know about first: Scalability. SVG describes shapes, WEBP stores a grid of pixels, and the engine rasterises at 150 dots per inch on the way across. That density is a deliberate choice: at the 72 dpi ImageMagick defaults to, an A4 SVG page comes out 595 pixels wide and reads as a failed conversion. Enlarge the WEBP afterwards and it blurs, because there is nothing left to redraw from.
What pixel size does the WEBP come out at?
Whatever 150 dots per inch makes of your SVG, and that density is a decision rather than a default. An SVG carries shapes and page dimensions, never pixels, so a scale has to be fixed before a single pixel is drawn. If you need another size, the SVG is the file to go back to: of the two it is the only one that still knows the shapes.
Is SVG to WEBP free?
There is a free allowance every month, and one SVG to WEBP conversion costs half a credit against it. When the allowance runs out the tool says so and stops, rather than quietly handing you a worse WEBP.