Figure Size & Resolution Calculator for Journal Submission (mm / inch / px / DPI)

One of the most common revision requests in manuscript submission is “figure resolution is insufficient.” There is really only one formula:

pixels = physical size (inch) × DPI
1 inch = 25.4 mm

So converting a column width given in millimeters to pixels:

px = mm ÷ 25.4 × DPI

The key point: DPI is not an intrinsic property of an image — physical size is. A 3000 × 2000 image is meaningless to call “300 dpi” on its own — only when you specify that it prints at 10 inches wide does it become 300 dpi. Journal requirements are therefore always given as a pair: column width + DPI.

Typical journal requirements (check your target journal’s author guidelines — these are order-of-magnitude references only):

For column widths, single-column is typically 85–90 mm, double-column 170–180 mm. Always check the author instructions of your target journal — values vary considerably between publishers.

Two practical tips:

• Use vector formats whenever possible. PDF, EPS, and SVG have no DPI concept, scale without loss, and most journals prefer them. Raster formats are only necessary for photographic content.
• Do not upscale a small image to meet the requirement. Interpolating from 150 dpi to 600 dpi adds no information; editors can spot this immediately. The correct approach is to go back to your graphics software and re-export at the target physical size.