The control throws on many aircraft models are specified in inches or millimeters. Not to worry- these values are easily converted to degrees! All you need to know is the control throw distance (as specified in your model's instructions) and the width (chord) of the control surface at the point where the control throw distance is specified, again, referring to your model's instructions. Commonly, control throws are specified at the widest part of the control surface (the widest where the measurement line is perpendicular to the hinge line).

Also, AeroPerfect's new MU-9000X USB has a built in utility for converting from inches to millimeters!

Knowing the point where the control throw distance is specified is only important if the control surface is tapered and does not have a constant chord. Otherwise, the control throw can be measured (or specified) anywhere along the length of the control surface.

Download this Conversion Utility Spreadsheet. You can "right-click" and select "save target as" or "save link as", depending on your browser. If your control throws are expressed as a fraction (e.g., 1-5/16), simply enter "1", then a space, and then "5/16". The spreadsheet will convert it to a decimal number.

Alternatively, you can divide the deflection which has been expressed in inches by the control surface width (also expressed in inches). Then, take the result and push the arcsine button on your calculator. Be sure to use the same units for the deflection and width.