Although the rest of the world seems to have gone metric, there are still a large number of people who prefer to use good old feet, inches, yards, grains, onces and ft/lbs. These calculators can convert between all of them. There is also a fill calculator to work out how many fills you should approx. get from your divers bottle. The full list of converters and calculators are: Fill Calculator, Energy Calculator, Length Conversion, Weight Conversion and Pressure Conversion.
From pellet BC and airrifle info. Inputs include muzzle velocity, sight heights, chronograph distance, ballistic coefficient, drag function, line of sight and cant angles and atmospheric conditions. Output options include variable ranges and choice of units for windage and drop (inches, MOA, and mils). Calculations are performed assuming the pellet is a point mass. Elevation and azimuth are iteratively corrected to ensure a correct zero.