Image Size, DPI and File Conversion

These pages cover the arithmetic behind figure files: how many pixels a given print width needs, what a file’s pixel count means at a chosen DPI, how large its uncompressed data is, and how to write a PNG or JPG out as a TIFF with the resolution you choose. Everything is calculated from the numbers you type or from files that are read in your browser and never uploaded. Pixels have no physical size until a resolution is chosen, so each tool asks for one and shows its formula.

Tools in this group

• DPI to Pixels — Enter the print size and the DPI to see how many pixels wide and high the image must be, and its megapixels.
• Image Size Calculator — Enter the pixel size, DPI and bit depth to see the print size, megapixels and uncompressed size, then try a new width.
• JPG to TIFF Converter — Choose one or more JPG files, set the DPI, colour and compression, and download baseline TIFF files. The conversion runs in this page; JPEG artifacts are not removed.
• Pixels to Inches — Enter a pixel count and a PPI to get the length in inches, cm and mm, or switch the direction to turn a length into pixels.
• PNG to TIFF Converter — Choose one or more PNG files, pick the DPI, colour and compression, and download baseline TIFF files. The conversion runs in this page and shows the real TIFF size.
• PPI to DPI — Enter the image pixels and the print width, or a screen resolution and diagonal, to get the PPI and the number to use as DPI in a layout program.
• Print Size Calculator — Enter the image pixels and the DPI to get the print size in inches and cm, and the largest size at other resolutions.