Then there is the "clock" method - basically the same as MJ uses but with a few more options - take the crosswind angle and imagine it on a clock face, so 15 degrees is 1/4 way round, 20 degrees 1/3 etc, so 40 degrees is 2/3 off, so a 20 knot wind I would call 21 for convenience giving me a 14kt crosswind component - for gusts just take the maximum gust and do the same if you need it.
At least with this you can apply it in the air using your head rather than fiddling with formula or a tablet.
N.b. Head/tailwind component can also be worked out by subtracting angle off from 90 and applying the same clock method.