杨-拉普拉斯方程序是一非线性偏微分方程，用来计算两静态流体界间因表面张力或壁张力造成的毛细管压力差，如水与空气。杨-拉普拉斯方程序链接了此压力差与表面形貌的关系，对静态毛细管表面的研究很有帮助。此方程序描述了液体界面间正向压力的平衡(界面厚度为零)。

：界面间的压力差、 γ：表面张力系数、 ：往界面外的单位法矢量、 ：平均曲率、 与：主要曲率半径

在此只考虑正向压力，因切线方向压力存在会导致界面的不稳定。

In physics, the Young–Laplace equation (/ˈjʌŋ ləˈplɑːs/) is a nonlinear partial differential equation that describes the capillary pressure difference sustained across the interface between two static fluids, such as water and air, due to the phenomenon of surface tension or wall tension, although usage on the latter is only applicable if assuming that the wall is very thin. The Young–Laplace equation relates the pressure difference to the shape of the surface or wall and it is fundamentally important in the study of static capillary surfaces. It is a statement of normal stress balance for static fluids meeting at an interface, where the interface is treated as a surface (zero thickness):