Nail the exact color off white in your design by using the code from any one of these systems for color identification.
|RGB||r: 253, g: 253, b: 253|
|HSL||h: 0°, s: 0%, l: 99%|
|HSV||h: 0°, s: 0%, v: 99%|
|CMYK||c: 0%, m: 0%, y: 0%, k: 1%|
If you're identifying color for pretty much anything digital, you're working in an RGB colorspace. If the project you're working on requires percentage representation, off white is made of 99% red, 99% green, and 99% blue.
If you're identifying color for a print project, you're most likely using a CMYK colorspace—the percentages are 0% cyan, 0% magenta, 0% yellow, 1% black.