Complex error propagation is reduced to formula and data entry into a Mathcad worksheet or an Excel spreadsheet. The Mathcad routine uses both symbolic calculus analysis and Monte Carlo methods to propagate errors in a formula of up to four variables. Graphical output is used to clarify the contributions to the final error of each of the individual variables as well as illustrate how well the results conform to the normal distribution. The Excel routine allows direct entry of the formula and evaluates the error by numerical approximation of the necessary partial derivatives. Students find the routines much more user friendly and informative than traditional error propagation techniques. (Contains 4 figures.)