base 7 is a positional numeral system with seven as its base. It uses 7 different digits for representing numbers. The digits for base 7 could be 0, 1, 2, 3, 4, 5, and 6.

conversion table

base 7	base 6	base 7	base 6
1	≈ 1	14	≈ 15
2	≈ 2	15	≈ 20
3	≈ 3	16	≈ 21
4	≈ 4	20	≈ 22
5	≈ 5	21	≈ 23
6	≈ 10	22	≈ 24
10	≈ 11	23	≈ 25
11	≈ 12	24	≈ 30
12	≈ 13	25	≈ 31
13	≈ 14	26	≈ 32