| Date | Iterations | Cost |
|---|---|---|
| 1/1/2000 | 64 | 6 |
| 7/1/2001 | 128 | 7 |
| 1/1/2003 | 256 | 8 |
| 7/1/2004 | 512 | 9 |
| 1/1/2006 | 1,024 | 10 |
| 6/1/2007 | 2,048 | 11 |
| 1/1/2009 | 4,096 | 12 |
| 6/1/2010 | 8,192 | 13 |
| 1/1/2012 | 16,384 | 14 |
| 7/1/2013 | 32,768 | 15 |
| 1/1/2015 | 65,536 | 16 |
| 6/1/2016 | 131,070 | 17 |
| 1/1/2018 | 262,144 | 18 |
| 6/1/2019 | 524,288 | 19 |
| 1/1/2021 | 1,048,576 | 20 |
| 7/1/2022 | 2,097,152 | 21 |
| 1/1/2024 | 4,194,304 | 22 |
| 6/1/2025 | 8,388,472 | 23 |
| 1/1/2027 | 16,777,216 | 24 |
| 6/1/2028 | 33,553,843 | 25 |
| 1/1/2030 | 67,108,864 | 26 |
| 7/1/2031 | 134,217,728 | 27 |
| 1/1/2033 | 268,435,456 | 28 |
| 1/1/2035 | 536,870,912 | 29 |
| 1/1/2036 | 1,073,741,824 | 30 |
| 6/1/2037 | 2,147,437,008 | 31 |
Souced: http://security.stackexchange.com/questions/17207/recommended-of-rounds-for-bcrypt