Excel vs. Mathcad for Engineering Calculations




Hey folks, as promised, here is my second installment on the topic of Excel vs. Mathcad for engineering calculations. In my first post I talked about conceptual differences between the two products and kept the details light. In this installment I will put a finer point on the differentiations.

WHITEBOARD VS FORMULA BAR

Mathcad is a document that emulates an engineer’s notebook or whiteboard. Using natural math notation, engineers can enter and evaluate their equations the way they learned them, and document or publish them without any extra steps or formatting needed. This ensures that calculations are easy to share and easy to verify for correctness.

 

In order for an engineer to perform calculations in Excel, they need to learn a cryptic formula syntax, translate their calculations, and enter them in a single line textbox. This is not a mathematical format suitable for publishing or sharing, and it is extremely difficult to review for correctness.

 

DOCUMENTATION

Mathcad is a robust numerical and symbolic processor, but it is also a word processor with many features that users of Microsoft Word will be familiar with. Engineers can document their ideas, design intent, anything that is relevant, and then easily produce professional-looking documents. With features such as text blocks, paragraphs, bullets, vertical and horizontal alignment, headers/footers, font face/size/style/color selections, page layout, margins selection, letter sizes and more, Mathcad provides engineers a rich environment for creating amazing looking documents.

Of course, Excel is not a word processor. Excel has a tabular interface, making it a poor choice for documenting anything. Engineers who use Excel often rewrite their math in Word using an equation editor (which is for presentation only, it does not calculate). In this scenario the engineer does their math in Excel, rewrites it and documents it in Word. If they change their calculation or input parameters they need to go back to Excel and start the process all over again. This is an incredible waste of time for a highly skilled, highly paid engineer.

UNITS

A significant benefit of using Mathcad is its handling of units. Engineers work with units; they measure time, temperature, velocity, energy, mass, distance, force, pressure and more. Mathcad allows engineers to assign units to their variables and to convert between units simply by reassigning them. Balancing and converting between units is absolutely critical to engineering calculations and Mathcad makes this very simple.

 

Excel has no facility for units on the terms of the calculations. Since Excel 2007 there is a CONVERT function which can convert a subset of singular units, for instance you can convert miles to kilometers. So you can insert into a cell CONVERT ( Number, From_Unit, To_Unit ) . This is such a limited attempt to support units. It is only for singular units, no support for gravity (m/s^2) or torque or rpms. Excel forces engineers to create conversion ratios and plug these magic numbers into their calculations. These magic numbers are hard to unravel or verify.

CALCULUS

Mathcad has a rich set of calculus functions. Mathcad’s calculus set includes integrals, derivatives, limits, summations and products – all using natural math type and supported by a complete set of trigonometric, hyperbolic, log and graphing functions. Mathcad supports ordinary and partial differential equations as well. Mathcad does calculus numerically and symbolically.

Excel has no integrals, no derivatives, no limits, no differential equations. It is very good at summations due to its accounting roots.

 

SYMBOLICS

Along with a powerful numerical engine, Mathcad has a very powerful symbolics engine under the hood.

Engineers can use symbolic evaluation to evaluate expressions containing operators, including integrals, derivatives, matrix operations, most matrix functions, summations, and products. When engineers evaluate arithmetic expressions symbolically, results are returned in terms of the symbols or variables in the original expression.

 

Excel has no symbolic calculation ability.

CONCLUSION

Along with the afore mentioned areas of functionality Mathcad provides math capabilities for Optimization, Design of Experiments, support for solving systems of Linear and Non-linear equations and support for scientific visualization. Mathcad was purposely built for engineers. Excel was built for accountants.