Nitrogen-free extract (NFE) is a calculated fraction in the proximate analysis of animal feeds, representing the soluble carbohydrates, principally sugars and starches, plus some hemicellulose and organic acids. It is not measured directly: analysts determine moisture, crude protein, crude fat, crude fibre, and ash, then subtract their sum from 100, with the remainder designated NFE. Because it is a difference figure, it accumulates the errors of all the other determinations and is the least precise fraction in the scheme. Despite its crudeness, NFE has been used for over a century in feed formulation to estimate the readily digestible energy of cereals, by-products, and forages. Modern feed evaluation increasingly replaces it with direct measurements of starch, sugars, and digestible fibre, but NFE still appears on older feed tables and in regulatory contexts.