频率是每单位时间重复事件的发生数量。它是在赫兹（Hz）中测量的。
1 oct = 1,999,999,999,999,999.8 fHz
1 fHz = 5.0000e-16 oct
例子:
将15 八度转换为Femtahertz：
15 oct = 29,999,999,999,999,996 fHz
| 八度 | Femtahertz |
|---|---|
| 0.01 oct | 19,999,999,999,999.996 fHz |
| 0.1 oct | 200,000,000,000,000 fHz |
| 1 oct | 1,999,999,999,999,999.8 fHz |
| 2 oct | 3,999,999,999,999,999.5 fHz |
| 3 oct | 5,999,999,999,999,999 fHz |
| 5 oct | 9,999,999,999,999,998 fHz |
| 10 oct | 19,999,999,999,999,996 fHz |
| 20 oct | 39,999,999,999,999,990 fHz |
| 30 oct | 59,999,999,999,999,990 fHz |
| 40 oct | 79,999,999,999,999,980 fHz |
| 50 oct | 99,999,999,999,999,980 fHz |
| 60 oct | 119,999,999,999,999,980 fHz |
| 70 oct | 139,999,999,999,999,980 fHz |
| 80 oct | 159,999,999,999,999,970 fHz |
| 90 oct | 179,999,999,999,999,970 fHz |
| 100 oct | 199,999,999,999,999,970 fHz |
| 250 oct | 499,999,999,999,999,940 fHz |
| 500 oct | 999,999,999,999,999,900 fHz |
| 750 oct | 1,499,999,999,999,999,700 fHz |
| 1000 oct | 1,999,999,999,999,999,700 fHz |
| 10000 oct | 19,999,999,999,999,996,000 fHz |
| 100000 oct | 199,999,999,999,999,970,000 fHz |
规则