Luckily there's an easy way to work it out, close enough anyway. You don't need any fancy charts, computers etc.
Suppose the wind is reported as 12 @ 350 and runway is 31.
First work out the relative bearing. RB = 350 - 31*10 = 40 degrees.
Now xwind component = wind speed * RB/60, i.e. 12 * 40/60 = 8. If RB is >60, then x-wind = wind speed.
This is as close as the reported winds are ever going to be accurate anyway, and dead easy to do in your head. Worst case error is about 15%.