I wouldn'tget all gung ho over LED calculators. There's no good reason to run an led at the full 20 mA.
For example, I'm running some high intensity red's off a 5 volt supply using 1k resistors for each light. That means they're only consuming 3 mA and they are still bright.
So if you calculate about 150 ohms, grab a bag of 220 ohm resistors.