Installing the PhysicalConstants Add-In adds a new menu under Excel’s ADD-INS tab. Click here to see how to load the PhysicalConstants Add-In using Mac Excel 2011.

You can insert a constant into your current worksheet by simply selecting it from the Physical Constants menu. (Or using Mac Excel, select it from the Constants menu, as shown here.)

Constants include units and are optionally labeled.

Change the units and the value of constant is automatically updated.

All physical constants have a function that can be used like any other Excel function in equations. For example, the peak wavelength emitted by a black body is given by the equation

where *c* is the speed of light, *h *is Planck’s constant, *k* is the Boltzmann constant, and T is the temperature. The temperature of our sun is 5778 degrees Kelvin. Entering this value into cell B1

Using the functions Clight() for the speed of light, Planck() for Planck’s constant, and Boltzmann() for the Boltzmann constant, we can write the Excel formula for the peak wavelength as

Be default all constants are returned in standard SI units, so the unit of the peak wavelength is meters.

If you’re unsure of the units, our DimensionEngine add-in can automatically determine the units for any Excel equation.