The most common thing people do with an SVG
Turning a vector into a PNG is the bread and butter of design hand-off. A developer receives a logo as SVG and needs a PNG for an email signature; a marketer has an icon set from a library and the ad platform only takes raster; a presenter wants a chart exported from a data tool to drop into slides. PNG is the natural target because it is lossless, keeps transparency with smooth 8-bit alpha edges, and opens in every application ever written.
How the rasterising step works
This page does not send the SVG anywhere. Your browser loads it into an image element, draws it onto a canvas at the image's intrinsic size, and the resulting pixels are encoded to PNG. The dimensions are taken from the width and height attributes on the root element. If they are absent, the browser may fall back to the viewBox, and if it still reports nothing the tool uses 512x512. There is no resolution setting on this page, so the practical way to control output size is to edit those two attributes in a text editor first. Doubling them gives you a crisp version for high-density screens; the vector redraws cleanly at any size, so nothing is upscaled.
Rendering happens in the browser's image context, which is deliberately restrictive. Scripts inside the SVG do not run, external images referenced by URL are not fetched, and web fonts declared through external stylesheets are not loaded. Text is drawn using fonts installed on your device, which is why a logo can come out in the wrong typeface. Ask for the text to be converted to outlines, or use a version of the SVG with the font embedded. Standard features such as gradients, filters, masks and clip paths render as they would on a web page.
What PNG keeps and what it cannot add
PNG is lossless, so there is no quality slider on this page; the encoder writes a 32-bit RGBA image at a fixed compression level. Transparency is preserved, including the partially transparent pixels along anti-aliased edges, which is the main advantage over SVG to JPG. Colours are treated as sRGB and the PNG carries no metadata, so an SVG with a title, description or author comment loses that information in the raster.
What PNG cannot do is give you back the scalability. A 512 pixel PNG scaled up to 2000 pixels in another program will be blurry, whereas the SVG would have been sharp. That is the reason to keep the vector alongside any raster you generate.
File sizes: a worked example
A 512x512 flat icon SVG of 6 KB typically becomes a PNG of 20 to 60 KB. A 1600x900 illustration with gradients usually lands between 300 KB and 1 MB, because gradients defeat PNG's compression. A 4000x4000 export of a detailed map can reach 3 to 5 MB and takes a couple of seconds to encode on a laptop. In each case the PNG is larger than the source; that is expected, since pixels replace instructions. If the result is too heavy for the web, SVG to WebP gets similar transparency at a fraction of the size, or run the PNG through the compressor. These figures are typical, not promises.
Limits worth knowing
Very large SVGs with tens of thousands of paths can be slow to rasterise and use a lot of memory, since the canvas holds four bytes per output pixel. SVGs that rely on external resources render with those parts missing. Files with no usable size information come out at 512x512, which is rarely what you want, so check the output dimensions and fix the attributes if needed. For favicons specifically, the favicon generator produces all the required sizes in one go rather than a single PNG.