Work out sheet resistance instantly with clear inputs, formula shown and shareable results.
Sheet resistance is resistivity divided by thickness, measured in ohms per square. A conductor's resistance is then simply sheet resistance times the number of squares (length over width), which makes layout resistance estimation a matter of counting squares.
Sheet resistance
Rs = rho / t; R = Rs x (L / W)
Because a square of any size has the same resistance: doubling both length and width leaves L/W unchanged. Only the aspect ratio matters.
Around 0.05-0.2 ohm/sq for thick copper metal layers, several ohms/sq for thin barrier metals, and tens to hundreds for polysilicon and diffusion.