差分，又名差分函数或差分运算，是数学中的一个概念。它将原函数 映射到 。差分运算，相应于微分运算，是微积分中重要的一个概念。

牛顿 · 莱布尼兹 · 柯西 · 黎曼
拉格朗日 · 拉普拉斯 · 欧拉

A finite difference is a mathematical expression of the form f(x + b) − f(x + a). If a finite difference is divided by b − a, one gets a difference quotient. The approximation of derivatives by finite differences plays a central role in finite difference methods for the numerical solution of differential equations, especially boundary value problems.