base 15 is a positional numeral system with fifteen as its base. It uses 15 different digits for representing numbers. The digits for base 15 could be 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, a, b, c, d, and e.

conversion table

base 15	duodecimal (base 12)	base 15	duodecimal (base 12)
1	≈ 1	b	≈ b
2	≈ 2	c	≈ 10
3	≈ 3	d	≈ 11
4	≈ 4	e	≈ 12
5	≈ 5	10	≈ 13
6	≈ 6	11	≈ 14
7	≈ 7	12	≈ 15
8	≈ 8	13	≈ 16
9	≈ 9	14	≈ 17
a	≈ a	15	≈ 18