Why phone photo sizes vary
Megapixels describe how many pixels are stored, but they do not directly determine file size. The file format and compression decide how efficiently those pixels are saved. A detailed scene can also require more data than a smooth sky at the same resolution.
HEIF, JPEG and RAW
HEIF is commonly smaller than JPEG at similar visual quality. High-quality JPEG keeps more data than a stronger JPEG compression setting. RAW or DNG files preserve substantially more camera information and are usually much larger.
Make the estimate more accurate
- Take several sample photos in the camera mode you plan to use.
- Find their average file size in the phone's file or photo information view.
- Compare that average with the calculator and choose the closest format estimate.