When the calculator icon appears above the table, data has changed and you need to click on that icon to recalculate the sheet. As you edit data, the (calculated) fields invalidated by your edits will be 'greyed out'. For example, choosing to solve for a different variable invalidates any previously calculated data in that variable's entry field(s).
If you choose to solve for Flow, the calculator will compute the volumetric flow rate, and - if you provided a density value, the mass flow rate also. The converse is not possible: the calculator will not solve for density given a mass flow rate.
If you choose to solve for something other than Flow, you must indicate which flow data you want the calculator to use - either Volume of Mass (weight actually). If you select Mass, you must provide the density value. If you select Volume, and provide the density value, the mass flow that corresponds with the volumetric flow you enter will be computed as a side-benefit.
After a recalc, you can bookmark this page and the data you have entered will be saved in the bookmark. This doesn't work if you have changed the data and not done a recalc.
!ERR! in the 'Result' field (the one solved for) indicates no solution was possible with the given input data (usually meaning a dimensional field contains zero).
You may use scientific notation in the input fields, e.g. 1.776e5. Positive or negative exponent signs, e.g. 1.776e-5, will be correctly interpreted.
If the 'Lookup' box is checked in the 'Pipe Internal Diameter' column, the calculator will attempt to supply the pipe i.d. for the type and size pipe you specify. If the data are not available, the calculator will use 0 for the i.d. There are one zillion different pipe types and sizes - only those commonly found in heavy process industries are available in the type selection dropdown. If the pipe type or size you need is not in the list, you will need to enter the pipe i.d. manually. The i.d. data used by the calculator is per ANSI B36.10/19-1996.