One iPhone photo, several images inside.
A HEIC file is a box of items: the photo (often cut into dozens of tiles), a thumbnail, sometimes a depth map or an HDR gain map, plus EXIF and XMP. PNG holds exactly one image. Open your photo and every item is listed from the file's own index, with what the PNG keeps. Decoding happens in your browser: natively where supported, otherwise with libheif loaded on demand.
Recent iPhones write HEIC at 10 bits per channel: 1,024 levels instead of 256. In a smooth sky those extra steps are the difference between a clean gradient and visible bands once you edit. PNG can store 16 bits, so it can keep them, but only if the decoder hands them over. Browsers decode to 8 bits, so this page writes 8-bit PNGs from your photo and says so. The lab below shows the difference on a 10-bit gradient built in numbers, written both ways by this page's own encoder.
Open a photo to see its declared bit depth.
HEIC uses the HEVC video codec to throw away what you won't notice. PNG keeps every decoded pixel exactly, sensor noise included, so a 2 MB photo becomes a file several times bigger. Measured on a generated 2400×1800 test photo:
Two settings decide what leaves your phone. Neither changes photos you've already taken, and both trade something away.
Yes, HEIC to PNG conversion is completely free with no signup, no watermark, and no usage limit. Convert as many files as you need.
No. The HEIC to PNG converter runs in your browser when your file is supported there, so the file stays on your device for that workflow, reducing server exposure for that workflow. Check which processing mode is in use before you upload anything sensitive.
Most HEIC to PNG conversions finish in under a minute. Larger files take proportionally longer, but everything happens locally so there is no sign-up wait.
That comes down to the formats at each end. A lossless conversion changes nothing you can measure. A lossy one shaves the file down and takes a small amount of quality with it.
Yes. The HEIC to PNG converter works on phones, tablets, and desktops in any modern browser including Chrome, Safari, Firefox, and Edge.