I was carrying out a calculation in raster calculator in ArcMap 10.4 where I multiplied two rasters together. Both rasters had the same extent, were snapped to each other and have the same pixels overlapping. When using the identify tool, I noticed that the result was different to if I worked it out myself. For example, the calculation for a particular pixel was 37.572238*90428390 (so should equal 3,397,596,991.03682). However the actual result from the raster calculator equaled 3,397,596,987.419. I also carried this out in QGIS to test and got another different result of 3,397,596,928.000.
Does anyone know why this happens? I thought it may have something to do with the precision as the numbers are so large...I know it isn't a huge difference but I need the result to be as accurate as possible.