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Using Reference IDs helps reduce duplicate inputs, keeps values consistent, and allows your calculations to automatically update when inputs change. This is especially important in engineering calculations, where the same value is often used in multiple places. By referencing a single value, you minimize the risk of input errors, avoid mismatched assumptions, and ensure that updates automatically track throughout the calculator. This not only saves time, but also improves accuracy, transparency, and confidence in the results. Anywhere you can type a value, you can use “Reference IDs”, also known as “Formula References” to use already inputted or calculated values. For any of the existing variables within a calculator, you can find the corresponding formula reference by opening the dropdown tab, which is located next to any calculated or inputted value- simply by clicking on the text. Image (2)
All of these values are unit-aware, meaning they’ll automatically handle unit conversions (we’ll also check that units are convertible).
These often differ per calculator, but some common ones are outlined below:

Common Beam Reference IDs

PropertyDescriptionReference IDUnits
Total Material LengthTypically in our beam calculators, this is the plan length from start to end including any intermediate supportsLft
Maximum Position From LeftMaximum position from the left, adjusted for support location based on the user’s selection of Plan or Inclined view.x_maxft
Total Start Trib. WidthTributary width at the start of the beam (at indicated start location)TW_sft
Typical Yield StrengthRelevant for our steel beam calculators, this value is either a user input or a typical value from the preferred specifications outlined in AISCFy, F_y_typpsi
Number of PliesRelevant for our wood beam calculators, used to indicate how many plies are fastened together along the flat siden_com-
In these calculators, values from Project Defaults can also be used. For example, typical bearing length is enter as projectDefault("l_b", 3.5) . Check out our Project Defaults Cheat Sheet for a more comprehensive list of what can be referenced in your calculators!

Common Column Reference IDs

PropertyDescriptionReference IDUnits
Column HeightTypically in our column calculators, this is the total height of the column from start to end including any intermediate supportsLft
Default Load Eccentricity for Bending about X-axisDefault value set for the axial eccentricity in bending about the strong axis.e_xin
Default Load Eccentricity for Bending about Y-axisDefault value set for the axial eccentricity in bending about the weak axis.e_yin
Total Start Trib. WidthTributary width at the start of the column for lateral distributed loads (at indicated start location)TW_sft
Typical Yield StrengthRelevant for our steel column calculators, this value is either a user input or a typical value from the preferred specifications outlined in AISCFy, F_y_typpsi
Number of PliesRelevant for our wood column calculators, used to indicate how many plies are fastened together along the flat siden_com-
Largest Hole SizeRelevant for our wood column calculators, used in consideration for drilled holes for holdown fastenersd_holein
You can use any of these values in a formula as well. For example, to place a support in the center of your column you can simply type in “L/2” for simplicity.