SVG is a vector format: shapes are stored as maths, so an SVG can be drawn at any size. PNG is a grid of pixels, which is what most apps, social networks, email clients and slide decks expect. Converting SVG to PNG means choosing a pixel size and drawing the vector at that size once.
This tool draws each SVG with your browser's own SVG engine. Pick 1x (the size written in the file), 2x or 4x for Retina and high-DPI screens, or type an exact width up to 8,192 px; the height follows the drawing's shape. Keep the background transparent or fill it with white or any colour. Up to 30 SVGs convert in one run, and you download them one by one or as a ZIP.
Limits: browsers do not load linked files when they draw an SVG as an image, so pictures, fonts or stylesheets that the SVG links to (rather than embeds) will be missing. The tool warns you when it finds them. Text set in a font your device doesn't have falls back to a default font, so convert text to outlines in your design app for an exact match. Very large outputs are capped at about 16.7 megapixels, the most iPhones can draw.