The soundtrack ONCE has sold 302,500 copies in Australia, Germany, Korea, New Zealand and United Kingdom.
ONCE certifications and sales
| Country / region | Sales | Certification / source | Certification date / sales as of | |
 Australia |
35,000 | 1x Gold |
Australia Sales: 35,000
Certification / note: 1x Gold
Certification Date / sales as of:
|
|
 Germany |
100,000 | 1x Gold | February 2023 |
Germany Sales: 100,000
Certification / note: 1x Gold
Certification Date / sales as of: February 2023
|
 Korea |
60,000 | RIAK / Gaon charts |
Korea Sales: 60,000
Certification / note: RIAK / Gaon charts
Certification Date / sales as of:
|
|
 New Zealand |
7,500 | 1x Gold |
New Zealand Sales: 7,500
Certification / note: 1x Gold
Certification Date / sales as of:
|
|
 United Kingdom |
100,000 | 1x Gold | 1 September, 2017 |
United Kingdom Sales: 100,000
Certification / note: 1x Gold
Certification Date / sales as of: 1 September, 2017
|
| Total sales | 302,500 | (in 5 countries) |
Total
Sales: 302,500
(in 5 countries)
|
Year-end chart performance for ONCE
| Chart 2007 | Rank | Sales |
| South Korean International Albums (Gaon) |
1 | 36,725 |
| Chart 2008 | Rank | Sales |
 Czech Albums (ČNS IFPI) |
9 | |
 US Albums (Billboard 200) |
99 | |
| Chart 2011 | Rank | Sales |
| South Korean International Albums (Gaon) |
90 | 2,063 |
| Chart 2012 | Rank | Sales |
| South Korean International Albums (Gaon) |
98 | 1,608 |
| Chart 2014 | Rank | Sales |
| South Korean International Albums (Gaon) |
55 | 1,768 |
| Chart 2015 | Rank | Sales |
| South Korean International Albums (Gaon) |
65 | 1,188 |