18 by MOBY has sold 1,585,000 copies in 32 countries. The album sold best in United States (500,000 copies), France (300,000 copies) and United Kingdom (300,000 copies).
18 certifications and sales
| Country / region | Sales | Certification / source | Certification date / sales as of | |
 Australia |
70,000 | 1x Platinum | OCTOBER 2002 |
Australia Sales: 70,000
Certification / note: 1x Platinum
Certification Date / sales as of: OCTOBER 2002
|
 Belgium |
50,000 | 1x Platinum |
Belgium Sales: 50,000
Certification / note: 1x Platinum
Certification Date / sales as of:
|
|
 France |
300,000 | 1x Platinum | 11 December, 2002 |
France Sales: 300,000
Certification / note: 1x Platinum
Certification Date / sales as of: 11 December, 2002
|
 Germany |
150,000 | 1x Gold | 2003 |
Germany Sales: 150,000
Certification / note: 1x Gold
Certification Date / sales as of: 2003
|
 Netherlands |
40,000 | 1x Gold | 2002 |
Netherlands Sales: 40,000
Certification / note: 1x Gold
Certification Date / sales as of: 2002
|
 New Zealand |
15,000 | 1x Platinum |
New Zealand Sales: 15,000
Certification / note: 1x Platinum
Certification Date / sales as of:
|
|
 Switzerland |
40,000 | 1x Platinum | 2002 |
Switzerland Sales: 40,000
Certification / note: 1x Platinum
Certification Date / sales as of: 2002
|
 United Kingdom |
300,000 | 1x Platinum | 19 July, 2002 |
United Kingdom Sales: 300,000
Certification / note: 1x Platinum
Certification Date / sales as of: 19 July, 2002
|
 United States |
500,000 | 1x Gold | 16 July, 2002 |
United States Sales: 500,000
Certification / note: 1x Gold
Certification Date / sales as of: 16 July, 2002
|
 Europe (IFPI) |
1,000,000 | 1x Platinum | 2002 |
Europe (IFPI) Sales: 1,000,000
Certification / note: 1x Platinum
Certification Date / sales as of: 2002
|
| Total sales | 1,585,000 | (in 32 countries) |
Total
Sales: 1,585,000
(in 32 countries)
|
Year-end chart performance for 18
| Chart 2002 | Rank | Sales |
| Australian Albums (ARIA) |
41 | >70,000 |
 Austrian Albums (Ö3 Austria) |
53 | |
| Belgian Albums (Ultratop Flanders) |
8 | |
| Belgian Albums (Ultratop Wallonia) |
10 | |
 Canadian Albums (SoundScan) |
66 | |
 Danish Albums (Hitlisten) |
74 | |
| Dutch Albums (Album Top 100) |
39 | |
 European Albums (Music & Media) |
13 | |
| French Albums (SNEP) |
17 | |
| German Albums (Offizielle Top 100) |
35 | |
| New Zealand Albums (RMNZ) |
31 | |
| Swiss Albums (Schweizer Hitparade) |
15 | |
| UK Albums |
46 | 360,000 |
| UK Artist Albums |
41 | 360,000 |
| US Albums (Billboard 200) |
160 | |
| Chart 2003 | Rank | Sales |
| Belgian Albums (Ultratop Flanders) |
61 | |
| Belgian Albums (Ultratop Wallonia) |
90 | |
| Dutch Albums (Album Top 100) |
96 | |
| French Albums (SNEP) |
120 |