The following is what GUP each belt color is:

 

Gup ITF TKD Belt color iTaekwonDo Belt Color Freedom Park Martial Arts

10

White

  White
9 White / Stripe White Orange
8 Yellow Yellow Gold
7 Yellow / Stripe Orange Green
6 Green Green Purple
5 Green / Stripe

Purple

Blue

4 Blue Blue Brown
3 Blue / Stripe Brown Red
2 Red Red Red / Stripe
1 Red / Stripe Poom Red Black

Recommended Black

Recommended Black Poom Recommended Black
Recommended Black Junior Black Belt N/A N/A
1st Dan 1st Dan 1st Dan 1st Dan
2nd Dan 2nd Dan 2nd Dan 2nd Dan
... ... ... ...

 

Vail Taekwon-Do, Desert Taekwon-Do, and Wolf's Taekwon-Do Pack Stripe is the next belt color. 

Southern Dragon Taekwon-Do the stripe is black.