Check this
Tae Kwon Do Rank

10th Gup White Belt
9th Gup White Belt With Yellow Stripe
8th Gup Yellow Belt
7th Gup Yellow Belt With Green Stripe
6th Gup Green Belt
5th Gup Green Belt With Blue Stripe
4th Gup Blue Belt
3rd Gup Blue Belt With Red Stripe
2nd Gup Red Belt
1st Gup Red Belt With Black Stripe
1st Dan (Il Dan) Black Belt
2nd Dan (Ee Dan) Black Belt
3rd Dan (Sam Dan) Black Belt
4th Dan (Sa Dan) Black Belt
5th Dan (Oh Dan) Black Belt
6th Dan (Yook Dan) Black Belt
7th Dan (Chil Dan) Black Belt
8th Dan (Pal Dan) Black Belt
9th Dan (Koo Dan) Black Belt