Many times some engineers are looking for formula to calculate UARFCN.
The UARFCN (UTRA Absolute Radio Frequency Channel Number) is the channel number representing the full 5 MHz UMTS carrier. Only 3.84MHz is used for transmission, while the 116 kHz acts as a built-in guard-band to adjacent UARFCN's (580kHz + 3840kHz + 580kHz = 5MHz). If an operator owns the adjacent frequency bands, it is possible to reduce the size of the UMTS carrier from 5MHz to 4.4 or 4.2 MHZ, but this is not recommended.
The UARFCN channel number is calculated according to it's frequency. If no offset is used, the frequency is simply multiplied by 5 to get the UARFCN (ex: 2132.8 MHZ * 5 = UARFCN 10664) If an offset is used the offset must be first subtracted from the frequency.